chem ib paper
-
Upload
embededodin -
Category
Documents
-
view
268 -
download
2
Transcript of chem ib paper
-
8/9/2019 chem ib paper
1/18
8808-6502
8 N08/4/PHYSI/HP2/ENG/TZ0/XX+
A3. This question is about ideal gases.
(a) State what is meant by an ideal gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(b) For an ideal gas
(i) dene internal energy.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(ii) state and explain how the internal energy and the absolute (kelvin) temperatureare related.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(This question continues on the following page)
0831
IB HL QUESTIONS ON THERMAL PHYSICS (page 1)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
2/18
8808-6502
9
Turn over
N08/4/PHYSI/HP2/ENG/TZ0/XX+
(Question A3 continued)
(c) Point A in thep-Vdiagram below represents the state of an ideal gas.
p/ 105Pa
4
2
0
A
0 4 8 12 16 20 24 28V/ 103m3
The number of moles of the gas is 0.64.
(i) Deduce that the temperature of the gas in state A is approximately 300 K.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(ii) A quantity Q of thermal energy is supplied to the gas at constant pressure.
The temperature of the gas increases to 900 K. Calculate the new volume of
the gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(iii) Determine the work done by the gas in this change of state.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(iv) State and explain, using the rst law of thermodynamics, whether the nal
temperature of the gas would be equal to, less than orgreater than 900 K if Q
had been absorbed at constant volume.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
0931
IB HL QUESTIONS ON THERMAL PHYSICS (page 2)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
3/18
8809-6502
24 N09/4/PHYSI/HP2/ENG/TZ0/XX+
(Question B3 continued)
Part 2 Thermodynamics
(a) The rst law of thermodynamics can be written as the following equation.
Q U W= +
Identify the symbols in this equation. [3]
Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(This question continues on the following page)
2428
IB HL QUESTIONS ON THERMAL PHYSICS (page 3)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
4/18
8809-6502
25
Turn over
N09/4/PHYSI/HP2/ENG/TZ0/XX+
(Question B3, part 2 continued)
(b) A xed mass of an ideal gas is contained in a cylinder by a piston. The friction between
the piston and cylinder wall is negligible.
Two procedures are carried out on the gas. The thermal energy input to the gas is thesame in both procedures.
Procedure 1 The gas is heated and expands at constant pressure with the piston free
to move. The temperature of the gas increases by 21 K.
Procedure 2 The gas is now brought back to its initial state and again heated with the
piston xed in position. The temperature of the gas increases by 35 K.
(i) State the name of the process in procedure 2.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(ii) Explain why the temperature change is greater in procedure 2 than in procedure 1.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[4]
(iii) In procedure 1, Uchanges by +120 J. Use the rst law of thermodynamics to
calculate the missing values in the table below. [3]
U/ J W / J Q / J
Procedure 1 +120 +200
Procedure 2 +200
2528
IB HL QUESTIONS ON THERMAL PHYSICS (page 4)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
5/18
8809-6502
6 N09/4/PHYSI/HP2/ENG/TZ0/XX+
A2. This question is about thermal energy transfer.
(a) A piece of copper is held in a ame until it reaches thermal equilibrium. The time it takes
to reach thermal equilibrium will depend on the thermal capacity of the piece of copper.
(i) Dene thermal capacity.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(ii) Outline what is meant by thermal equilibrium in this context.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(b) The piece of copper is transferred quickly to a plastic cup containing water. The thermal
capacity of the cup is negligible. The following data are available.
Mass of copper = 0.12 kg
Mass of water = 0.45 kg
Rise in temperature of water = 30K
Final temperature of copper = 308K
Specic heat capacity of copper = 390 J kg K1
Specic heat capacity of water = 4200 J kg K1
(i) Use the data to calculate the temperature of the ame.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
(ii) Explain whether the temperature of the ame is likely to be greater or less than
your answer to (b)(i).
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
0628
IB HL QUESTIONS ON THERMAL PHYSICS (page 5)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
6/18
2208-6508
26 M08/4/PHYSI/HP2/ENG/TZ1/XX+
(Question B3 continued)
Part 2 Thermodynamics
(a) State, by reference to energy exchanges, the difference between a heat pump and a
heat engine.
Heat pump: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat engine: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(b) The diagram shows the ideal shape of a pressure-volume relationship (P-V) for the
working substance during one cycle of a steam engine.
P
B A610 Pap = 1.2
3
1mV = 0.10
3
2mV = 0.40
V
The part of the cycle labelled AB is an isobaric isothermal change of phase.
(This question continues on the following page)
2633
IB HL QUESTIONS ON THERMAL PHYSICS (page 6)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
7/18
-
8/9/2019 chem ib paper
8/18
2208-6508
30 M08/4/PHYSI/HP2/ENG/TZ1/XX+
(Question B4, part 1 continued)
(d) The engine that drives the conveyor belt in (c) operates in a cycle. In part of this cycle,
air is compressed in a cylinder of the engine such that the pressure and the temperature of
the air increases. Assuming that the air in the cylinder behaves as an ideal gas, outline how
the kinetic model of an ideal gas accounts for this increase in temperature and pressure.
temperature:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
pressure:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[7]
(This question continues on the following page)
3033
IB HL QUESTIONS ON THERMAL PHYSICS (page 8)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
9/18
2208-6508
12 M08/4/PHYSI/HP2/ENG/TZ1/XX+
(Question B1 part 1 continued)
(d) Another bullet is red from a different gun into a large block of wood. The block remains
stationary after impact and the bullet melts completely. The temperature rise of the block
is negligible. Use the data to estimate the minimum impact speed of the bullet.
mass of bullet 10 kg3
= 5.2
specic heat capacity of the material of the bullet 130 J kg K1 1
=
latent heat of fusion of the material of the bullet 870 J kg1
=
melting point of the material of the bullet 330 C=
initial temperature of bullet 30 C=
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[5]
(This question is continued on the following page)
1233
IB HL QUESTIONS ON THERMAL PHYSICS (page 9)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
10/18
2209-6508
6 M09/4/PHYSI/HP2/ENG/TZ1/XX+
A3. This question is about internal energy, heat and ideal gases.
(a) The internal energy of a piece of copper is increased by heating.
(i) Explain what is meant, in this context, by internal energy and heating.
Internal energy: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heating: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
(ii) The piece of copper has mass 0.25 kg. The increase in internal energy of the copper
is 1 2 103. J and its increase in temperature is 20 K. Estimate the specic heat
capacity of copper.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(This question continues on the following page)
0630
IB HL QUESTIONS ON THERMAL PHYSICS (page 10)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
11/18
2209-6508
7 M09/4/PHYSI/HP2/ENG/TZ1/XX+
0730
(Question A3 continued)
(b) One mole of an ideal gas is heated at constant pressure. The increase in temperature of
the gas is 30.0 K. The energy transferred to the gas is 623 J and the work done is 249 J.
Determine
(i) the change in internal energy of the gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
(ii) the thermal capacity of the gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(c) Another mole of the same gas is heated at constant volume starting from the same state as
that in (b). Suggest whether the thermal capacity in this case is equal to, greater than orless than the answer in b(ii).
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
IB HL QUESTIONS ON THERMAL PHYSICS (page 11)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
12/18
2208-6514
15
Turn over
M08/4/PHYSI/HP2/ENG/TZ2/XX+
B2. This question is in twoparts. Part 1is about latent heat and specic heat and Part 2is about
force elds.
Part 1 Latent heat and specic heat
(a) (i) Denespecic latent heat of vaporization.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(ii) Energy is supplied to a boiling liquid at a constant rate. Describe, in terms of
molecular behaviour, why the temperature of the liquid remains constant.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
(This question continues on the following page)
1531
IB HL QUESTIONS ON THERMAL PHYSICS (page 12)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
13/18
2208-6514
16 M08/4/PHYSI/HP2/ENG/TZ2/XX+
(Question B2, part 1 continued)
(b) A student determines the latent heat of vaporization of water by an electrical method.
An electrical heater is used to boil water. When the water is boiling at a steady rate,
the mass of water evaporated per minute is determined. The mass is determined for
two different powers of the heater and the results are shown in the table below.
power of heater / W mass of water evaporated per minute / g
80.0
35.0
1.89
0.70
The power of the heater is determined using an ammeter and a voltmeter.
(i) The heater is labelled 9.0 V, 80.0 W. In the space below, draw an electrical circuit toshow how the heater may be used correctly with a constant 12 V supply to provide
different powers to the heater. Include the ammeter and voltmeter in your circuit. [2]
12 V
(ii) Calculate the current in the heater for a power output of 80.0 W.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(iii) Use the data in the table above to determine a value for the specic latent heat of
vaporization of water.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[4]
(This question continues on the following page)
1631
IB HL QUESTIONS ON THERMAL PHYSICS (page 13)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
14/18
2208-6514
17
Turn over
M08/4/PHYSI/HP2/ENG/TZ2/XX+
(Question B2, part 1 continued)
(c) In one particular make of electric kettle, the heater must always be immersed in water
when the kettle is in use. The minimum volume of water that can be heated is 650 cm3.
The kettle is used six times each day to boil water for a single cup of tea. The cup has avolume of 350 cm3. The mass of 1.0 cm3of water is 1.0 g.
(i) Calculate the mass of water that is heated, but not used, during one day.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(ii) The initial temperature of the water in the kettle before heating is 18C.
The specic heat capacity of water is 4.2 103J kg1K1. Deduce that the
electrical energy wasted each day is 6.2 105J.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(iii) The cost of 1.0 MJ of electrical energy is 3.5 cents. Estimate the cost of the energy
that is used each year to heat water that is not used to make tea.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(This question continues on the following page)
1731
IB HL QUESTIONS ON THERMAL PHYSICS (page 14)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
15/18
2208-6514
6 M08/4/PHYSI/HP2/ENG/TZ2/XX+
A3. This question is about an ideal gas and entropy.
(a) A xed mass of an ideal gas is compressed from volume V1 to volume V2 at
constant temperature. The variation with volume V of the pressure p of the gas is
shown below.
p
V2 V1 V
On the diagram above, draw a line to show the variation of pressure pas the volume of
the gas is changed from V1to V
2without allowing any thermal energy to enter or leave
the gas. [2]
(b) On the diagram in (a), identify
(i) with the letter G, the line that represents the change that requires the greater amount
of work done on the gas. [1]
(ii) by shading an area of the diagram, the part of the diagram that represents the
difference between the work done in the two changes. [1]
(c) For the compression of the gas at constant temperature, deduce what change, if any,
occurs in the entropy of the gas and of its surroundings. [3]
the gas: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
the surroundings: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0631
IB HL QUESTIONS ON THERMAL PHYSICS (page 15)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
16/18
2209-6514
23
Turn over
M09/4/PHYSI/HP2/ENG/TZ2/XX+
B2. This question is in two parts. Part 1 is about ideal gases. Part 2 is about the use of
fossil fuels.
Part 1 Ideal gases
(a) The atoms or molecules of an ideal gas are assumed to be identical hard elastic spheres
that have negligible volume compared with the volume of the containing vessel.
(i) State twofurther assumptions of the kinetic theory of an ideal gas.
1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(ii) Suggest why only the average kinetic energy of the molecules of an ideal gas is
related to the internal energy of the gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[3]
(This question continues on the following page)
IB HL QUESTIONS ON THERMAL PHYSICS (page 16)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
17/18
2209-6514
24 M09/4/PHYSI/HP2/ENG/TZ2/XX+
(Question B2, part 1 continued)
(b) An ideal gas is contained in a cylinder by means of a frictionless piston.
piston
cylinder
ideal gas
At temperature 290 K and pressure 4.8 105Pa, the gas has volume 9.2 10
4m3.
(i) Calculate the number of moles of the gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(ii) The gas is compressed isothermally to a volume of 2.3 104m3. Determine the
pressurepof the gas.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(iii) The gas is now heated at constant volume to a temperature of 420 K. Show that the
pressure of the gas is now 2.8106Pa.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
(This question continues on the following page)
IB HL QUESTIONS ON THERMAL PHYSICS (page 17)
DULWICH COLLEGE SHANGHAI
-
8/9/2019 chem ib paper
18/18
2209-6514
25
Turn over
M09/4/PHYSI/HP2/ENG/TZ2/XX+
(Question B2, part 1 continued)
(c) The gas in (b)(iii) is now expanded adiabatically so that its temperature and pressure
return to 290 K and 4.8105Pa respectively. This state is shown below as point A.
p
V
(i) Using the axes above sketch a pressure-volume (p-V) diagram for the changes in
(b)(ii), (b)(iii) and (c). [3]
(ii) On your diagram in (c)(i), identify with the letter H any change orchanges where
the gas does external work on its surroundings. [1]
(iii) Describe how ap-Vdiagram may be used to estimate a value for the useful work
done in one cycle of operation of an engine.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
(This question continues on the following page)
IB HL QUESTIONS ON THERMAL PHYSICS (page 18)