55A2 Matter questions1.When a gas in a cylinder is compressed at constant temperature by a piston, the pressure of the gas increases. Consider the following three statements.I.The rate at which the molecules collide with the piston increases.II.The average speed of the molecules increases.III.The molecules collide with each other more often. Which statement(s) correctly explain the increase in pressure?A.I onlyB.II onlyC.I and II onlyD.I and III only(1)2.(a)State what is meant by an ideal gas................................................................................................................................................................................................................................................................................................................................................................................................................(2) (b)The internal volume of a gas cylinder is 2.0 102 m3. An ideal gas is pumped into the cylinder until the pressure becomes 20 MPa at a temperature of 17C.Determine(i)the number of moles of gas in the cylinder;.................................................................................................................................................................................................................................................................................................................................................................................(2)(ii)the number of gas atoms in the cylinder..................................................................................................................................................................................................................................................................................................................................................................................(2) (c)(i)Using your answers in (b), determine the average volume occupied by one gas atom.......................................................................................................................................................................................................................................................(1)(ii)Estimate a value for the average separation of the gas atoms..................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 9 marks)3.A gas is contained in a cylinder fitted with a piston as shown below.When the gas is compressed rapidly by the piston its temperature rises because the molecules of the gasA.are squeezed closer together.B.collide with each other more frequently.C.collide with the walls of the container more frequently.D.gain energy from the moving piston.(1)4.A container holds 20 g of neon (mass number 20) and also 8 g of helium (mass number 4).What is the ratio ?A.0.4B.0.5C.2.0D.2.5(1)5.A gas is contained in a cylinder fitted with a piston as shown below.When the gas is compressed rapidly by the piston its temperature rises because the molecules of the gasA.are squeezed closer together.B.collide with each other more frequently.C.collide with the walls of the container more frequently.D.gain energy from the moving piston.(1)6.A fixed mass of an ideal gas is heated at constant volume. Which one of the following graphs best shows the variation with Celsius temperature t with pressure p of the gas?(1)7.This question is about an ideal gas.(a)The pressure P of a fixed mass of an ideal gas is directly proportional to the kelvin temperature T of the gas. That is,P T .State the relation between the(i)pressure P and the volume V for a change at constant temperature...................................................................................................................................................................................................................................................(1)(ii)volume V and kelvin temperature T for a change at a constant pressure...................................................................................................................................................................................................................................................(1)(b)The ideal gas is held in a cylinder by a moveable piston. The pressure of the gas is P1, its volume is V1 and its kelvin temperature is T1. The pressure, volume and temperature are changed to P2, V2 and T2 respectively. The change is brought about as illustrated below.State the relation between(i)P1, P2, T1 and T ...................................................................................................................................................................................................................................................(1)(ii)V1, V2, T and T2...................................................................................................................................................................................................................................................(1) (c)Use your answers to (b) to deduce, that for an ideal gasPV = KT,where K is a constant...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 8 marks)8.An ideal gas is contained in a cylinder by a piston. The volume of the gas is decreased by moving the piston rapidly in the direction shown.The average speed of the gas molecules is initially increased because the moleculesA.have a smaller volume in which to move.B.make more collisions in unit time with the cylinder walls and piston.C.have energy transferred to them as they collide with the moving piston.D.make more collisions with each other in unit time.(1)9.Which of the following correctly describes the changes in the kinetic energy of the molecules and the potential energy of the molecules as a liquid changes phase to a gas?kinetic energy of the moleculespotential energy of themoleculesA.no changeincreasesB.no changeno changeC.increasesincreasesD.increasesno change(1) 10.The graph below shows the variation with absolute temperature T of the pressure p of one mole of an ideal gas having a volume V. R is the molar gas constant.Which of the following is the best interpretation of the intercept on the temperature axis and the gradient of the graph?Intercept on temperature axis / KGradient of graphA. 273B.0C.0D. 273(1)11.When the volume of a fixed mass of an ideal gas is reduced at constant temperature, the pressure of the gas increases.This pressure increase occurs because the atoms of the gasA.collide more frequently with each other.B.collide more frequently with the walls of the containing vessel.C.are spending more time in contact with the walls of the containing vessel.D.are moving with a higher mean speed.(1)12.Gas leaks slowly out of a cylinder of constant volume. The temperature of the gas in the cylinder does not change. Which of the following is constant for the gas molecules in the cylinder?A.The number striking unit area of surface in unit timeB.The number of the collisions between molecules per unit timeC.The number per unit volumeD.The average speed(1)13.A fixed quantity of an ideal gas is compressed at constant temperature. The best explanation for the increase in pressure is that the moleculesA.are moving faster.B.are colliding more frequently with the container walls.C.exert greater forces on each other.D.are colliding more frequently with each other.(1)14.The equation of state for an ideal gas, pV = nRT, describes the behaviour of real gasesA.only at low pressures and large volumes.B.only at high temperatures.C.only at large volumes and large pressures.D.at all pressures and volumes.(1)15.The temperature of an ideal gas is reduced. Which one of the following statements is true?A.The molecules collide with the walls of the container less frequently.B.The molecules collide with each other more frequently.C.The time of contact between the molecules and the wall is reduced.D.The time of contact between molecules is increased.(1)16.This question is about an ideal gas.(a)The pressure P of a fixed mass of an ideal gas is directly proportional to the kelvin temperature T of the gas. That is,P T.State(i)the relation between the pressure P and the volume V for a change at constant temperature;..................................................................................................................................................................................................................................................(1)(ii)the relation between the volume V and kelvin temperature T for a change at a constant pressure...................................................................................................................................................................................................................................................(1)(b)The ideal gas is held in a cylinder by a moveable piston. The pressure of the gas is P1, its volume is V1 and its kelvin temperature is T1.The pressure, volume and temperature are changed to P2, V2 and T2 respectively. The change is brought about as illustrated below.State the relation between(i)P1, P2, T1 and T ...................................................................................................................................................................................................................................................(1)(ii)V1, V2, T and T2...................................................................................................................................................................................................................................................(1)(c)Use your answers to (b) to deduce, that for an ideal gasPV = KTwhere K is a constant...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 8 marks) 17.A sample of an ideal gas is contained in a cylinder. The volume of the gas is suddenly decreased. A student makes the following statements to explain the change in pressure of the gas.I.The average kinetic energy of the gas atoms increases.II.The atoms of the gas hit the walls of the cylinder more frequently.III.There are more atoms that are able to collide with the walls of the cylinder.Which of these statements is true?A.I and II onlyB.I and III onlyC.II and III onlyD.I, II and III(1)18.Container X below has volume V and holds n moles of an ideal gas at kelvin temperature T. Container Y has volume 2V and holds 3n moles of an ideal gas also at kelvin temperature T.The pressure of the gas in X is PX and in Y is PY.The ratio isA.B.C.5.D.6.(1)19.An ideal gas is kept in a container of fixed volume at a temperature of 30C and a pressure of 6.0 atm. The gas is heated at constant volume to a temperature of 330C.The new pressure of the gas is aboutA.0.60 atm.B.3.0 atm.C.12 atm.D.66 atm.(1)20.Two ideal gases X and Y, are contained in a cylinder at constant temperature. The mass of the atoms of X is m and of Y is 4m.Which one of the following is the correct value of the ratioA.1B.2C.4D.16(1)21.The nuclear notation for lithium-7 is. Which one of the following is the mass of 1 mol of lithium-7?A.10 gB.7 gC.4 gD.3 g(1) 22.Which two values of temperature are equivalent to the nearest degree when measured on the Kelvin and on the Celsius scales of temperature?Kelvin scaleCelsius scaleA.40313B.273100C.31340D.3730(1)23.The distance between the 0C and 100C marks on a mercury-in-glass thermometer is 20 cm. When the thermometer bulb is placed in a mixture of ice and salt, the mercury level is 4 cm below the 0C mark. The temperature of the mixture isA.+20C.B.+5C.C.5C.D.20C.(1)24.The kelvin temperature of an object is a measure ofA.the total energy of the molecules of the object.B.the total kinetic energy of the molecules of the object.C.the maximum energy of the molecules of the object.D.the average kinetic energy of the molecules of the object.(1)25.Three bodies X, Y and Z are at temperatures X, Y and Z respectively. Thermal energy passes freely from Y to X and also from Z to X, as illustrated below. The direction of flow of thermal energy, if any, between Y and Z is unknown. What can be deduced about the temperatures X, Y and Z?A.X = (Y +Z)B.Y = ZC.Y > XD.X > Z26.A temperature scale is to be constructed using the property X of a substance. Which of the following must be a characteristic of the property X?A.The value of the property must be zero at zero kelvin.B.The property must increase with increase of temperature.C.The property must have a different value at each temperature to be measured.D.The value of the property must vary linearly with kelvin temperature.(1)27.The length of the mercury column in a thermometer is L100 at 100C and L0 at 0C.Which of the following gives the temperature when the length of the mercury column is LT?A.B.C.D.(1)28.Two bodies are brought into thermal contact with each other. No thermal energy transfer takes place between the bodies. It may be deduced therefore, that the bodies must have the sameA.specific heat capacity.B.heat capacity.C.temperature.D.internal energy.(1)29.A solid is at an initial temperature of 500 K. The solid is heated so that its temperature rises by 50 K.What are the initial temperature and the temperature rise of the solid, as measured on the Celsius scale of temperature?initial temperaturetemperature riseA.227C50CB.227C323CC.773C50CD.773C323C(1)30.During an experiment, a solid is heated from 285 K to 298 K.Which one of the following gives the rise in temperature, in deg C, and the final temperature, inC, of the solid?Rise in temperature in deg CFinal temperature in CA.13571B.1325C.286571D.28625(1)31.Some students were asked to design and carry out an experiment to determine the specific latent heat of vaporization of water. They set up the apparatus shown below. The current was switched on and maintained constant using the variable resistor. The readings of the voltmeter and the ammeter were noted. When the water was boiling steadily, the reading of the top-pan balance was taken and, simultaneously, a stopwatch was started. The reading of the top-pan balance was taken again after 200 seconds and then after a further 200 seconds.The change in reading of the top-pan balance during each 200 second interval was calculated and an average found. The power of the heater was calculated by multiplying together the readings of the voltmeter and the ammeter. (a)Suggest how the students would know when the water was boiling steadily...........................................................................................................................................................................................................................................................................(1) (b)Explain why a reading of the mass lost in the first 200 seconds and then a reading of the mass lost in the next 200 second interval were taken, rather than one single reading of the mass lost in 400 seconds.(2)...............................................................................................................................................................................................................................................................................................................................................................................................................The students repeated the experiment for different powers supplied to the heater. A graph of the power of the heater against the mass of water lost (the change in balance reading) in 200 seconds was plotted. The results are shown below. (Error bars showing the uncertainties in the measurements are not shown.) (c)(i)On the graph above, draw the best-fit straight line for the data points.(1)(ii)Determine the gradient of the line you have drawn.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)In order to find a value for the specific latent heat of vaporization L, the students used the equationP = mL,where P is the power of the heater and m is the mass of water evaporated per second.(d)Use your answer for the gradient of the graph to determine a value for the specific latent heat of vaporization of water.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (e)The theory of the experiment would suggest that the graph line should pass through the origin. Explain briefly why the graph does not pass through the origin...........................................................................................................................................................................................................................................................................(2)(Total 12 marks)32.The specific latent heat of vaporization of a substance is the quantity of energy required toA.raise the temperature of a unit mass of a substance by one degree Celsius.B.convert a unit mass of liquid to vapour at constant temperature and pressure.C.convert a unit mass of solid to vapour at constant temperature and pressure.D.convert a unit mass of liquid to vapour at a temperature of 100C and a pressure of one atmosphere.(1)33.The specific heat capacity of a metal block of mass m is determined by placing a heating coil in its centre, as shown in the diagram above.The block is heated for time t and the maximum temperature change recorded is . The ammeter and voltmeter readings during the heating are I and V respectively.Which one of the following is not a source of error in the experiment?A.Some thermal energy is retained in the heater.B.The thermometer records the temperature at one point in the block.C.Some thermal energy is lost from the variable resistor in the circuit.D.The block is heated at its centre, rather than throughout its whole volume.(1)34.The specific heat capacity of a metal block of mass m is determined by placing a heating coil in its centre, as shown in the diagram above.The block is heated for time t and the maximum temperature change recorded is . The ammeter and voltmeter readings during the heating are I and V respectively.The specific heat capacity is best calculated using which one of the following expressions?A.c = B.c = C.c = D.c = (1)35.A substance changes from solid to liquid at its normal melting temperature. What change, if any, occurs in the average kinetic energy and the average potential energy of its molecules?Average kinetic energyAverage potential energyA.constantconstantB.increasesconstantC.increasesdecreasesD.constantincreases(1)36.The specific latent heat of vaporization of a substance is greater than its specific latent heat of fusion becauseA.boiling takes place at a higher temperature than melting.B.thermal energy is required to raise the temperature from the melting point to the boiling point.C.the volume of the substance decreases on freezing but increases when boiling.D.the increase in potential energy of the molecules is greater on boiling than on melting.(1)37.This question is about modelling the thermal processes involved when a person is running.When running, a person generates thermal energy but maintains approximately constant temperature.(a)Explain what thermal energy and temperature mean. Distinguish between the two concepts...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4) The following simple model may be used to estimate the rise in temperature of a runner assuming no thermal energy is lost.A closed container holds 70 kg of water, representing the mass of the runner. The water is heated at a rate of 1200 W for 30 minutes. This represents the energy generation in the runner.(b)(i)Show that the thermal energy generated by the heater is 2.2 106 J..................................................................................................................................................................................................................................................................................................................................................................................(2) (ii)Calculate the temperature rise of the water, assuming no energy losses from the water. The specific heat capacity of water is 4200 J kg1 K1........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (c)The temperature rise calculated in (b) would be dangerous for the runner. Outline three mechanisms, other than evaporation, by which the container in the model would transfer energy to its surroundings.........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(6) A further process by which energy is lost from the runner is the evaporation of sweat.(d)(i)Describe, in terms of molecular behaviour, why evaporation causes cooling........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(ii)Percentage of generated energy lost by sweating: 50%Specific latent heat of vaporization of sweat: 2.26 106 J kg1Using the information above, and your answer to (b) (i), estimate the mass of sweat evaporated from the runner............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. (3) (iii)State and explain two factors that affect the rate of evaporation of sweat from the skin of the runner...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 25 marks)38.(a)A small lump of ice (a hailstone) at 0C falls to the Earths surface. When the hailstone hits the surface, all of the kinetic energy of the hailstone is transferred to thermal energy in the ice. Calculate the minimum speed of the hailstone so that it just melts when it hits the surface. The specific latent heat of fusion of ice is 340 kJ kg1.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (b)By reference to your answer in (a), suggest whether hailstones are likely to melt on hitting the Earths surface................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 5 marks)39.Some liquid is contained in a shallow dish that is open to the atmosphere. The rate of evaporation of the liquid does not depend onA.the temperature of the liquid.B.the temperature of the atmosphere.C.the depth of the liquid.D.the pressure of the atmosphere.(1)40.The specific latent heat of fusion of a substance is defined as the amount of thermal energy required to change the phase ofA.the substance at constant temperature.B.unit mass of the substance to liquid at constant temperature.C.unit mass of the substance at constant temperature.D.the substance to gas at constant temperature.(1)41.This question is about the change of phase (state) of ice.A quantity of crushed ice is removed from a freezer and placed in a calorimeter. Thermal energy is supplied to the ice at a constant rate. To ensure that all the ice is at the same temperature, it is continually stirred. The temperature of the contents of the calorimeter is recorded every 15 seconds.The graph below shows the variation with time t of the temperature of the contents of the calorimeter. (Uncertainties in the measured quantities are not shown.) (a)On the graph above, mark with an X, the data point on the graph at which all the ice has just melted.(1)(b)Explain, with reference to the energy of the molecules, the constant temperature region of the graph..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) The mass of the ice is 0.25 kg and the specific heat capacity of water is 4200 J kg1 K1.(c)Use these data and data from the graph to(i)deduce that energy is supplied to the ice at the rate of about 530 W........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(ii)determine the specific heat capacity of ice.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(iii)determine the specific latent heat of fusion of ice.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 12 marks) 42.This question is about the change of phase (state) of ice.A quantity of crushed ice is removed from a freezer and placed in a calorimeter. Thermal energy is supplied to the ice at a constant rate. To ensure that all the ice is at the same temperature, it is continually stirred. The temperature of the contents of the calorimeter is recorded every 15 seconds. The graph below shows the variation with time t of the temperature of the contents of the calorimeter. (Uncertainties in the measured quantities are not shown.) (a)On the graph above, mark with an X, the data point on the graph at which all the ice has just melted.(1) (b)Explain, with reference to the energy of the molecules, the constant temperature region of the graph..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)The mass of the ice is 0.25 kg and the specific heat capacity of water is 4200 Jkg1K1.(c)Use these data and data from the graph to(i)deduce that energy is supplied to the ice at the rate of about 530 W........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (ii)determine the specific heat capacity of ice.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (iii)determine the specific latent heat of fusion of ice.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) (d)State what property of the molecules of the ice is measured by a change in entropy......................................................................................................................................(1)(e)State, in terms of entropy change, the second law of thermodynamics...........................................................................................................................................................................................................................................................................(1) (f)State what happens to the entropy of water as it freezes. Outline how this change in entropy is consistent with the second law of thermodynamics....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 18 marks)43.As part of an experiment to determine the latent heat of vaporisation of water, a student boils some water in a beaker using an electric heater as shown below.The student notes two sources of error.Error 1: thermal energy is lost from the sides of the beakerError 2: as the water is boiling, water splashes out of the beakerWhich of the following gives the correct effect of these two errors on the calculated value for the specific latent heat?Error 1Error 2A.IncreaseDecreaseB.IncreaseNo changeC.DecreaseIncreaseD.DecreaseNo change(1) 44.This question is about specific heat capacity and specific latent heat.(a)Define specific heat capacity...........................................................................................................................................................................................................................................................................(1) (b)Explain briefly why the specific heat capacity of different substances such as aluminium and water are not equal in value.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)A quantity of water at temperature is placed in a pan and heated at a constant rate until some of the water has turned into steam. The boiling point of the water is 100C.(c)(i)Using the axes below, draw a sketch-graph to show the variation with time t of the temperature of the water. (Note: this is a sketch-graph; you do not need to add any values to the axes.)(1) (ii)Describe in terms of energy changes, the molecular behaviour of water and steam during the heating process...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(5)Thermal energy is supplied to the water in the pan for 10 minutes at a constant rate of 400 W. The thermal capacity of the pan is negligible.(d)(i)Deduce that the total energy supplied in 10 minutes is 2.4 105 J............................................................................................................................(1) (ii)Using the data below, estimate the mass of water turned into steam as a result of this heating process.initial mass of water= 0.30 kginitial temperature of the water = 20Cspecific heat capacity of water= 4.2 103 J kg1 K1specific latent heat of vaporization of water= 2.3 106 Jkg1..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (iii)Suggest one reason why this mass is an estimate.......................................................................................................................................................................................................................................................(1)(Total 14 marks)45.A liquid is contained in a dish open to the atmosphere.Which one of the following contains three factors that affect rate of evaporation of the liquid?A.Temperature of the liquidSurface areaSpecific latent heat of vaporizationB.Temperature of the liquidMass of liquidSpecific latent heat of vaporizationC.Surface areaMass of liquidTemperature of the liquidD.Mass of liquidSurface areaSpecific latent heat of vaporization(1) 46.This question is about an experiment to measure the temperature of a flame.(a)Define heat (thermal) capacity...........................................................................................................................................................................................................................................................................(1) A piece of metal is held in the flame of a Bunsen burner for several minutes. The metal is then quickly transferred to a known mass of water contained in a calorimeter.The water into which the metal has been placed is stirred until it reaches a steady temperature.(b)Explain why(i)the metal is transferred as quickly as possible from the flame to the water;......................................................................................................................................................................................................................................................(1) (ii)the water is stirred.......................................................................................................................................................................................................................................................(1) The following data are available:heat capacity of metal= 82.7 J K1heat capacity of the water in the calorimeter= 5.46 102 J K1heat capacity of the calorimeter= 54.6 J K1initial temperature of the water= 288 Kfinal temperature of the water= 353 K (c)Assuming negligible energy losses in the processes involved, use the data to calculate the temperature T of the Bunsen flame...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 7 marks)47.A liquid is evaporating, causing the liquid to cool. The temperature of the liquid decreases becauseA.the number of liquid molecules is decreasing.B.the mean kinetic energy of the liquid molecules is decreasing.C.the pressure above the liquid surface is increasing.D.the rate of evaporation is increasing.(1) 48.Data analysis questionAt high pressures, a real gas does not behave as an ideal gas. For a certain range of pressures, it is suggested that the relation between the pressure P and volume V of one mole of the gas at constant temperature is given by the equationPV = A + BPwhere A and B are constants.In an experiment to measure the deviation of nitrogen gas from ideal gas behaviour, 1 mole of nitrogen gas was compressed at a constant temperature of 150 K. The volume V of the gas was measured for different values of the pressure P. A graph of the product PV of pressure and volume was plotted against the pressure P and is shown below. (Error bars showing the uncertainties in measurements are not shown). (a)Draw a line of best fit for the data points.(1) (b)Use the graph to determine the values of the constants A and B in the equationPV = A + BP.Constant A...................................................................................................................................................................................................Constant B.....................................................................................................................................................................................................................................................................................................................................(5) (c)State the value of the constant B for an ideal gas......................................................................................................................................(1) (d)The equation PV = A + BP is valid for pressures up to 6.0 107 Pa.(i)Determine the value of PV for nitrogen gas at a pressure of 6.0 107 Pa..................................................................................................................................................................................................................................................................................................................................................................................(2) (ii)Calculate the difference between the value of PV for an ideal gas and nitrogen gas when both are at a pressure of 6.0 107 Pa..................................................................................................................................................................................................................................................................................................................................................................................(2)(e)In the original experiment, the pressure P was measured to an accuracy of 5% and the volume V was measured to an accuracy of 2%. Determine the absolute error in the value of the constant A................................................................................................................................................................................................................................................................................................................................................................................................................(3)(Total 14 marks)49.The specific latent heat of vaporization of a substance is defined as the amount of thermal energy required toA.change a liquid to vapour at constant pressure.B.change a liquid to vapour at constant temperature.C.change unit mass of liquid to vapour at constant pressure.D.change unit mass of liquid to vapour at constant temperature.(1)50.This question is about thermal physics.(a)Explain why, when a liquid evaporates, the liquid cools unless thermal energy is supplied to it.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (b)State two factors that cause an increase in the rate of evaporation of a liquid.1. .................................................................................................................................2. .................................................................................................................................(2) (c)Some data for ice and for water are given below.Specific heat capacity of ice= 2.1 103 J kg1 K1Specific heat capacity of water= 4.2 103 J kg1 K1Specific latent heat of fusion of ice= 3.3 105 J kg1A mass of 350 g of water at a temperature of 25C is placed in a refrigerator that extracts thermal energy from the water at a rate of 86 W.Calculate the time taken for the water to become ice at 5.0C..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(Total 9 marks)51.A substance is heated at a constant rate. The sketch graph shows the variation with time t of the temperature q of the substance.In which region or regions of the graph must there be more than one phase of the substance present?A.WX and YZB.WX onlyC.WX, XY and YZD.XY only(1) 52.The physics of cooling(a)Explain what is meant by the temperature of a substance.......................................................................................................................................................................................................................................................................(2)A thermometer is placed in a liquid contained in an open beaker. The reading of the thermometer is recorded at regular intervals. The variation with time t of the temperature q is shown below.(b)The temperature of the surroundings is 20C. On the graph continue the line to show the variation with time of the temperature for the next 3000 s.(2) (c)By reference to the graph, state and explain the rate of loss of thermal energy from the substance between(i)0 and 600 s;...........................................................................................................................................................................................................................................................................................................................................................................(2)(ii)600 and 1800 s...........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)The mass of the liquid is 0.11 kg and the specific heat capacity of the liquid is 1300 J kg1 K1.(d)(i)Use the graph to deduce that the rate of loss of thermal energy at time t = 600 s is approximately 4 W.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (ii)Calculate the specific latent heat of fusion of the liquid.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(Total 16 marks)53.The physics of cooling(a)Explain what is meant by the temperature of a substance.......................................................................................................................................................................................................................................................................(2)A thermometer is placed in a liquid contained in an open beaker. The reading of the thermometer is recorded at regular intervals. The variation with time t of the temperature q is shown below (b)The temperature of the surroundings is 20C. On the graph continue the line to show the variation with time of the temperature for the next 3000 s.(2)(c)By reference to the graph, state and explain the rate of loss of thermal energy from the substance between(i)0 and 600 s;...........................................................................................................................................................................................................................................................................................................................................................................(2) (ii)600 and 1800 s..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4) The mass of the liquid is 0.11 kg and the specific heat capacity of the liquid is 1300 J kg1 K1.(d)(i)Use the graph to deduce that the rate of loss of thermal energy at time t = 600 s is approximately 4 W.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(ii)Calculate the specific latent heat of fusion of the liquid.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(Total 16 marks) 54.The specific heat capacity c of a solid block of mass m is determined by heating the block and measuring its temperature. The graph below shows the variation of the temperature T of the block with the thermal energy Q transferred to the block.The gradient of the line is equal toA.B.C.mc.D.(1)55.This question is about specific heat capacity and a domestic shower.(a)Define the term specific heat capacity..........................................................................................................................................................................................................................................................................................................................................................................................................(1) (b)Equal masses of two different solid substances A and B are at the same temperature. The specific heat capacity of substance A is greater than the specific heat capacity of substance B. The two substances now have their temperatures raised by the same amount.Explain which substance will have the greater increase in internal energy assuming both remain in the solid phase.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(c)In an experiment to measure the specific heat capacity of a metal, a piece of the metal is immersed in boiling water and left there for several minutes. It is then transferred quickly into some cold water in a calorimeter. The water is stirred and the maximum temperature of the water is recorded.(i)State why the metal is left in the boiling water for several minutes...................................................................................................................................................................................................................................................(1) (ii)Write down a word equation for the thermal energy QM lost by the metal to the water...................................................................................................................................................................................................................................................(1) (iii)Write down a word equation for the thermal energy QW gained by the water in the calorimeter...................................................................................................................................................................................................................................................(1)(iv)A value of the specific heat capacity of the metal may be calculated from (ii) and (iii) by assuming that QM = QW.State why in practice, this assumption leads to an error in the calculated value of the specific heat capacity...................................................................................................................................................................................................................................................(1) (d)The diagram below shows part of the heating circuit of a domestic shower.Cold water enters the shower unit and flows over an insulated heating element. The heating element is rated at 7.2 kW, 240 V. The water enters at a temperature of 14C and leaves at a temperature of 40C. The specific heat capacity of water is 4.2 103 J kg1 K1.(i)Describe how thermal energy is transferred from the heating element to the water..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(ii)Estimate the flow rate in kg s1 of the water.......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(iii)Suggest two reasons why your answer to (b) is only an estimate.1...............................................................................................................................................................................................................................2...............................................................................................................................................................................................................................(2)(iv)Calculate the current in the heating element when the element is operating at 7.2 kW............................................................................................................................................................................................................................................................................................................................................................................(2)(v)Explain why, when the shower unit is switched on, the initial current in the heating element is greater than the current calculated in (iv)............................................................................................................................................................................................................................................................................................................................................................................(2)(e)In some countries, shower units are operated from a 110 V supply. A heating element operating with a 240 V supply has resistance R240 and an element operating from a 110 V supply has resistance R110.(i)Deduce, that for heating elements to have identical power outputs........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (ii)Using the ratio in (i), describe and explain one disadvantage of using a 110 V supply for domestic purposes.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 25 marks)56.A large mass M of ice of specific latent heat L is at its melting point (0C). A small mass m of water at q C is poured on to the block of ice. The specific heat capacity of water is S. Which one of the following is a correct expression for the mass of ice melted?A.B.C.D.(1)57.Heating water electricallyThe diagram below shows part of the heating circuit of a domestic shower.Cold water enters the shower unit and flows over an insulated heating element. The heating element is rated at 7.2 kW, 240 V. The water enters at a temperature of 14C and leaves at a temperature of 40C. The specific heat capacity of water is 4.2 103 J kg1 K1.(a)Describe how thermal energy is transferred from the heating element to the water................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3) (b)Estimate the flow rate in kg s1 of the water...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(c)Suggest two reasons why your answer to (b) is only an estimate.1...................................................................................................................................................................................................................................................2...................................................................................................................................................................................................................................................(2) (d)Calculate the current in the heating element when the element is operating at 7.2 kW..........................................................................................................................................................................................................................................................................................................................................................................................................(2) (e)Explain why, when the shower unit is switched on, the initial current in the heating element is greater than the current calculated in (d)..........................................................................................................................................................................................................................................................................................................................................................................................................(2)(f)In some countries, shower units are operated from a 110 V supply. A heating element operating with a 240 V supply has resistance R240 and an element operating from a 110 V supply has resistance R110.(i)Deduce, that for heating elements to have identical power outputs........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(ii)Using the ratio in (i), describe and explain one disadvantage of using a 110 V supply for domestic purposes.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 18 marks)58.The heat capacity of a solid body is defined asA.the thermal energy required to increase the bodys temperature by one degree.B.the maximum thermal energy that must be supplied to melt the solid.C.the total kinetic energy of the solids molecules.D.the average kinetic energy of the solids molecules.(1)59.Specific latent heat(a)Define specific latent heat of fusion.......................................................................................................................................................................................................................................................................(1) (b)Solar radiation is incident on a pond of area 12 m2. The pond is covered by a layer of ice of thickness 3.0 cm. The temperature of the ice is 0.0C.(i)The density of ice is 900 kg m3. Deduce that the mass of ice on the pond is approximately 320 kg...................................................................................................................................................................................................................................................(2) (ii)The average power per unit area incident on the ice over a period of 6.0 hours is 340 W m2. Deduce that the energy incident on the pond in this time is 8.8 107 J...................................................................................................................................................................................................................................................(1)(iii)The specific latent heat of fusion of ice is 330 kJ kg1. Determine whether all the ice on the pond will melt in the 6.0 hour time period.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) (iv)State one assumption you made in reaching your answer to (b)(iii)...................................................................................................................................................................................................................................................(1) (c)During the night, the air temperature drops to 5C. The ice that melted during the day freezes again. Outline one mechanism by which thermal energy is lost by the ice...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 9 marks)60.The specific heat capacity of an object is defined as the thermal energy required to raise the temperature ofA.the volume of the object by 1 K.B.unit volume of the object by 1 K.C.the mass of the object by 1 K.D.unit mass of the object by 1 K.(1) 61.A metal block of mass M is heated. The graph shows the variation with thermal energy H supplied to the block of its temperature rise q.The gradient of the straight-line graph is n. The specific heat capacity of the metal isA.B.C.Mn.D.n.(1)62.A metal can containing water is heated using a heating coil as shown below.The water is boiling at a constant rate. The mass of water boiled away per unit time is M1 for a heater power P1. When the heater power is increased to P2, the mass boiled away per unit time is M2. Heat losses to the atmosphere are not negligible.Which of the following expressions gives the specific latent heat of vaporization of the water?A.B.C.D.(1)63.Gases and liquids(a)Describe two differences, in terms of molecular structure, between a gas and a liquid.1...................................................................................................................................................................................................................................................2...................................................................................................................................................................................................................................................(2)(b)The temperture of an ideal gas is a measure of the average kinetic energy of the molecules of the gas. Explain why the average kinetic energy is specified..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(c)Define heat (thermal) capacity.......................................................................................................................................................................................................................................................................(1)(d)Water is heated at a constant rate in a container that has negligible heat capacity. The container is thermally insulated from the surroundings.The sketch-graph below shows the variation with time of the temperature of the water.The following data are available:initial mass of water= 0.40 kginitial temp of water= 20Crate at which water is heated= 300 Wspecific heat capacity of water= 4.2 103 J kg1C1(i)State the reason why the temperature is constant in the region AB...................................................................................................................................................................................................................................................(1)(ii)Calculate the temperature q at which the water starts to boil......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(5)(e)All the water is boiled away 3.0 103 s after it first starts to boil. Determine a value for the specific latent heat L of vaporization of water.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(Total 13 marks)64.A liquid is heated in a well-insulated container. The power input to the liquid and its specific heat capacity are known.Which of the following quantities must be known in order to calculate the rate at which the temperature increases?A.The time for which the liquid is heatedB.The initial temperature of the liquidC.The final temperature of the liquidD.The mass of the liquid(1)65.Temperature and thermal energy(a)Outline how a temperature scale is constructed.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(b)Discuss why even an accurate thermometer may affect the reliability of a temperature reading.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2) (c)(i)Define specific heat capacity............................................................................................................................................................................................................................................................................................................................................................................(2)(ii)The table below gives data for water and ice.specific heat capacity of waterspecific latent heat of fusion of ice4.2 kJ kg1 K1330 kJ kg1A beaker contains 450 g of water at a temperature of 24C. The thermal (heat) capacity of the beaker is negligible and no heat is gained by, or lost to, the atmosphere. Calculate the mass of ice, initially at 0C, that must be mixed with the water so that the final temperature of the contents of the beaker is 8.0C..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(4)(d)(i)Distinguish between evaporation and boiling.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(ii)Explain, in terms of molecular behaviour, why boiling involves a transfer of thermal energy with no change in temperature.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(Total 15 marks) 66.The specific latent heat of fusion of a substance is the quantity of thermal energy required to convert, at constant temperature,A.a solid to a liquid.B.unit mass of solid to liquid.C.a liquid to a solid.D.unit mass of liquid to solid.(1)67.Magnetic and electrical force fieldsA proton is accelerated from rest in a vacuum through a potential difference of 420 V. The proton then enters a region ABCD of uniform magnetic field as shown.The magnetic field is directed into the plane of the paper. The field strength is 15 mT.(a)(i)Calculate the speed of the proton as it enters the region of the magnetic field............................................................................................................................................................................................................................................................................................................................................................................(2)(ii)The path of the proton as drawn on the diagram is in the plane of the paper. The proton enters the region ABCD of the magnetic field and leaves through the side BC. On the diagram above, draw the path of the proton within and beyond the region ABCD of the magnetic field. Label the path P.(2)(iii)Determine the magnitude of the force due to the magnetic field that acts on the proton while the proton is in the region ABCD.........................................................................................................................................................................................................................................................................................................................................................................(2) (b)A uniform electric field is applied in the region ABCD. A second proton enters the region ABCD with the same velocity as the proton in (a). The electric field is adjusted so that, as the proton enters this region, the force on the proton due to the electric field is equal but opposite in direction to the force due to the magnetic field.(i)On the diagram provided on page 22, draw an arrow to show the direction of the electric field. Label this arrow E.(1)(ii)Determine the magnitude of the electric field strength............................................................................................................................................................................................................................................................................................................................................................................(2) (c)(i)State Lenzs law............................................................................................................................................................................................................................................................................................................................................................................(2)(ii)Explain how Lenzs law is consistent with the law of conservation of energy............................................................................................................................................................................................................................................................................................................................................................................(2)(d)A rectangular window PQRS has a metal frame. The window is hinged on the vertical side RS as shown below.The window has width RQ of 32 cm and height PQ of 95 cm. When closed, the window is normal to the horizontal component of the Earths magnetic field of field strength 18 mT. The window is opened through an angle of 90 in a time of 0.34 s. (i)Assuming that the flux linkage changes at a constant rate, calculate the emf induced in the frame of the window as it is being opened.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)(ii)State across which parts of the frame the emf is induced. Explain your reasoning.....................................................................................................................................................................................................................................................................................................................................................................................................................