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II.. PPrrooppeerrttiieess ooff LLIIQQUUIIDDSS:: 1) Of solids, liquids, and gases, the ___________________ common state of matter is the liquid

state.

a) _________________ can exist only within a relatively narrow range of temperature and pressure.

2) The kinetic-molecular theory (KMT) can be used to explain the behavior of

liquids. Assumptions of the kinetic-molecular theory of liquids include the following:

a) Liquids consist of tiny _______________(ions, atoms, or molecules).

b) Liquid particles are __________________ together.

c) __________________________ (intermolecular or IM forces)

between liquid particles are significant.

d) Liquid particles are in constant, random _____________________.

• Particles appear to vibrate around __________________ points and are __________________ (intermolecular forces) together than gas particles

e) Particles in a liquid are ________________ ordered than particles in a gas.

f) The average KE of particles in the liquid state is generally ________________ than the average KE of those particles in the gas state.

3) _________________= a measure of the amount of space occupied by a sample of matter

a) Liquids have a __________________ volume (which changes only slightly with changes

in temperature and pressure).

• Explanation using KMT: Attractive forces keep particles close together (in definite volume)

4) _______________________ a) Liquids take the shape of their container (have ________________ shape).

• Explanation using KMT: Attractive forces keep particles close together but particles are in constant motion (they are NOT bound together in fixed positions) � Particles do not move away from each other but can slide/glide past each

other

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5) _____________________ = a substance that can flow and therefore take the shape of its container

a) Liquids (and gases) are fluids.

• Explanation using KMT: Attractive forces keep particles together but particles are in constant motion (they are NOT bound together in fixed positions) � Particles do not move away from each other but can slide/glide past each

other

6) _______________________ = the ratio of mass to volume for a sample of matter

a) Liquids have a relatively high density compared to gases.

• Explanation using KMT: Liquid particles are relatively close to each other (more particles in a particular volume, amount of space)

7) ______________________________ = the ability of a sample

of matter to have its volume reduced under pressure

a) Liquids are relatively _______________________.

• Explanation using KMT: Liquid particles are packed close together (there is not much room/empty space to push them closer)

8) __________________________ = the spontaneous mixing of two or more substances

a) Liquids will diffuse through other liquids (if they will dissolve).

b) Diffusion is _________________ between liquids than between gases.

• Explanation using KMT: Gas particles move in constant, random motion and mix with each other while liquid particles are closely packed (attractive forces impede particle movement), constantly hitting each other, and changing paths.

9) ______________________ = resistance of a liquid to flow

• Ex: cold molasses

• __________ viscosity = thick; Low viscosity = ___________

a) Some liquids have a low viscosity while others have a high viscosity.

• Explanation using KMT: Substances with a high viscosity typically have strong attractive forces (IM forces) between the particles and substances with a low viscosity typically have weak attractive forces (IM forces) between the particles

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b) Ex: Look at the picture below.

• Which substance has the lowest viscosity? _____ • Which substance has the highest? _______

10) ______________________________= The energy required to increase the surface area of a liquid by a given amount; results from an uneven distribution of attractive forces.

a) It is a measure of the inward pull by particles in the interior.

• The stronger the attraction between particles, the greater the surface tension o Examples:

1. ______________________

2. _________________ (water striders)

3. ________________ = liquids ability to flow up thin tubes; going against gravity

• Ex: Water going up plant stems

4. _______________________:

A. A Unique Liquid – WATER!

1) Water is the most ___________________________liquid!

2) Water is a_____________________________________:

a) Because of the difference in electronegativity between the strongly electronegative oxygen atom and the less electronegative hydrogen atoms, the H-O covalent bonds in the water molecule are____________________________.

• The water molecule has an unequal distribution of charge; so it is a ____________________________________!

b) Electrons in each covalent bond spends more time close to the______________ nucleus, giving oxygen a partial negative charge

c) Diagram of 5 water molecules. Notice that each water molecule can form _________________________________!

Attract to container (H2O)

Attract to each other (Hg)

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3) Water is a unique substance since the solid state (ice) is __________ dense than the liquid state.

a) Because of the hydrogen bonding, the arrangement of the molecules in the solid crystalline structure take up _______________ space, yet have the same mass; making ice less dense than liquid water.

IIII.. CCHHAANNGGIINNGG SSTTAATTEESS OOFF MMAATTTTEERR::

•• ________________________= transitioning from one state of matter to another.

oo Phase changes are physical changes not chemical changes

oo Occurs with a change of __________________(form of energy).

�� Heat energy is either absorbed or released

oo Does _______ change the temperature!

A. How can there be a change in heat during a phase change without a change in temperature?

o Energy exchanges are _______ changes in kinetic energy – so temperature remains

constant.

o Heat energy is used to change the ________________________between the molecules

� The amount of energy will depend on the ____________________of the intermolecular forces.

•• Phase changes happen when certain points are reached

oo Ex: ___________________________= liquid turns into a solid

�� Energy is ______________as the molecules bond to one another.

•• When it gets colder, most solids ___________________in size.

oo Exceptions– __________expands!

oo Ex:_____________________________________= Solid turns into a liquid

�� Ex: a cube of ice sitting on a counter.

�� When a solid reaches the temperature of its melting point it can become a liquid.

�� Energy is ______________________!

�� Added energy is used to break the IM forces between the molecules.

�� Ex: water freezes and melts at 0°C

oo Ex: _______________________________= gas turns into a liquid

�� When a gas reaches the temperature of its condensation point, it becomes a liquid.

�� Energy is __________________ from the gas particles!

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oo Energy changes with certain phase changes:

BB.. MMeellttiinngg vvss.. FFrreeeezziinngg

1. _______________________: as temp increases, the particles collide with each other more often and with a greater force so they move further apart (less intermolecular forces); the ordered arrangement of the solid state breaks down—solid has melted!

2. _________________________: in the liquid state there will be a temp. (and pressure)

at which average energy of the particles become low enough that attractive forces will hold the particles together (increasing the intermolecular forces) in an orderly arrangement. The particles settle into an order arrangement and form a solid.—liquid freezes!

PPoossssiibbllee CChhaannggeess ooff SSttaattee::

NNaammee CChhaannggee ooff SSttaattee EExxaammppllee

Solid �Liquid Ice � water

Solid �Gas Dry ice � CO2 gas

Liquid � Solid Water � ice

Liquid � Gas Liquid bromine � bromine vapor

Gas � Liquid Water vapor � water

Gas � Solid Iodine vapor � Solid Iodine

• ___________________= gas phase of a substance that is normally a SOLID or LIQUID at room temperature

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C. EVAPORATION OF A LIQUID:

1) Systems:

a) ___________________________= everything

b) _____________________________= the part of the universe on which attention is focused

c) ______________________________= everything in the universe except the system

(usually only concerned with the surroundings near the system)

d) ___________________________= system in which matter cannot enter and leave the system (but energy can enter and leave)

• Ex: Flask with stopper

e) _______________________= system in which matter can enter and leave the system (also energy can enter and leave)

• Ex: Open beaker or flask

2) “Vaporization” and “Evaporation”.

a) _______________________= a general term for the process by which a liquid changes to a gas

b) ________________________= the process by which particles escape from the surface of

a non-boiling liquid and enter the gas state (evaporation is a type of vaporization)

3) Use KMT to explain the evaporation of liquids:

a) particles of a liquid are moving at different _______________ and have different KE

b) In order for a liquid particle to evaporate (escape into the vapor/gas state) it must:

• be at the __________________of the liquid

• posses enough KE to _____________________the attractive forces (IM forces) holding it in the liquid state

c) Picture representation of evaporation:

4) Some liquids evaporate more readily than

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other liquids.

a) _____________________________= a liquid that will evaporate readily

• Ex: Rubbing Alcohol

b) Explanation using KMT:

• There are relatively _____________________________of attraction (IM forces) between particles in a volatile liquid (less kinetic energy is required for a particle to break attractive forces (IM forces) and escape into the vapor state).

c) ________________________________= a liquid that will evaporate slowly

• Ex: water

d) Explanation using KMT:

• There are relatively ______________________of attraction (IM forces) between particles in a nonvolatile liquid (more kinetic energy is required for a particle to break attractive forces (IM forces) and escape into the vapor state).

DD.. BBOOIILLIINNGG

1) ___________________________= the rapid vaporization of a liquid, which occurs

when a liquid is heated to its boiling point.

a) Vaporization occurs throughout

b) Molecules in the ______________ of the liquid form water vapor bubbles.

c) Water vapor bubbles are less dense than the surrounding liquid, will rise to

the surface and escape from the liquid.

2) ______________________________________= the temperature at which the

equilibrium vapor pressure of the liquid is EQUAL to the pressure exerted on the liquid by the

surrounding environmental pressure (often atmospheric pressure).

a) If atmospheric pressure is greater than the liquids equilibrium vapor pressure, the bubble

will _______________________.

3) _____________________________________= the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature

a) A vapor in equilibrium with its liquid contains gas/vapor particles that _____________ with a surface exerting pressure.

4) Different substances have different equilibrium vapor pressures at a given temperature. a) KMT Explanation:

• If equilibrium vapor pressure is ________ � substance _________________readily

o Substances with a high equilibrium vapor pressure (volatile) typically have ____________________________________(IM forces) between the

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particles (less kinetic energy is required for a particle to break attractive forces (IM forces) and escape into the vapor state).

� Ex: Rubbing alcohol

• If equilibrium vapor pressure is ________ � substance does_______

evaporate readily

o Substances with a low equilibrium vapor pressure (nonvolatile) typically have ______________________________(IM forces) between the particles (more kinetic energy is required for a particle to break attractive forces (IM forces) and escape into the vapor state).

� Ex: water

5) Different liquids boil at different temperatures

o A liquid that boils at a LOW temp. and evaporates rapidly at room temp. is said to be _____________________________

- Ex: rubbing alcohol = 82.6°C; Ethanol = 78.4°C; Acetone = 56°C

6) Different elevations affect boiling points:

o As elevation _________________________(lower atmospheric pressure), boiling point ________________________.

o Cooking time ____________________ at high elevations because food does not get as

____________.

� Ex: Water’s boiling points: - Sea level- 100 ◦C - Denver- 94◦C - Mt. Everest - 70◦C

o Ex: Making a cup of tea:

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E. Evaporation vs. Boiling • Evaporation:

� Is a ________________phenomenon

� Particles escape from the surface of a ___________________liquid and enter the _______________________________

• Boiling:

o At the boiling point, the equilibrium vapor pressure is _______________ to atmospheric pressure so bubbles form

o Vaporization occurs ____________________________

o Liquid will _________boil if its equilibrium vapor pressure is _________________than the atmospheric pressure!

III. EEQQUUIILLIIBBRRIIUUMM::

A. A Liquid-Vapor System at Equilibrium

1) Any __________________________(including evaporation) can be represented as follows:

liquid + heat energy → vapor (___________________ process)

2) _________________________________can be represented as follows:

vapor → liquid + heat energy (___________________________process)

3) ___________________________ = a dynamic condition in which two opposing physical or

chemical changes occur at equal rates in a given closed system

4) A ______________________________ at equilibrium can be represented as follows:

liquid + heat energy vapor

a) If the system is at _________________________, vaporization and condensation will occur at equal rates but there will be no net change (net amount of liquid and vapor will not change - the number of particles leaving the liquid equals the number reentering the liquid).

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5) A liquid-vapor system reaching equilibrium (refer to figure below):

a) Only liquid is present but particles begin to _______________________.

b) Evaporation continues at the _________ rate. There is a relatively low concentration of vapor. Vapor particles are _________________ to liquid at a lower rate than evaporation.

c) Concentration of vapor has increased to the point at which the rates of

_________________ and __________________ are ______________. Equilibrium has been reached; the number of particles leaving the liquid equals the number reentering the liquid.

B. Le Chatelier’s Principle

1) ____________________________________________= When a system at equilibrium is disturbed by application of a stress, it attains a ______________equilibrium position that minimizes the stress

a) A stress is usually a change in ___________________, ________________, or __________________________.

b) A system at equilibrium stays at equilibrium unless a stress is applied.

c) After a stress is applied to a system at equilibrium the system cannot reestablish the original equilibrium conditions.

d) After a stress is applied to a system at equilibrium the system partially counteracts the stress and, in time, establishes a new equilibrium.

e) Example involving change of ____________________:

In the equation: 2NO(g) + O2(g) 2NO2(g)

o If you add more NO(g) the equilibrium shifts to the

• ___________________producing more NO2(g)

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o If you add more NO2(g) the equilibrium shifts to the

• __________________producing more NO(g) and O2(g)

f) 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g) + energy

� Determine the direction of the shift resulting from each applied stress and

provide reasoning:

1) Addition of NO(g)

� Shift = ____________

� Reasoning = to consume some of the added NO

2) Removal of O2 (g)

� Shift = ___________

� Reasoning = to replace the O2 (g)

g) Consider a liquid-vapor system at equilibrium represented as follows:

liquid + heat energy vapor

� If temperature increases the forward reaction is temporarily favored until a NEW equilibrium is established. � Equilibrium shifts to the __________________

� The new equilibrium will contain __________ vapor particles.

� The new equilibrium will contain ____________liquid particles.

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IIVV.. PPhhaassee DDiiaaggrraamm:: 1) ___________________________= a graph of pressure versus temperature that shows which

phase a substance exists in under different conditions of temperature and pressure. a) Can be used to predict what phase any substance will be in for any combination of

temperature and pressure.

b) What phase of matter would carbon be in at 5000°C and 104 atm? ________________

2) _______________________________= indicates the temperature and pressure conditions at

which the solid, liquid, and gas (vapor) of a substance can coexist at equilibrium

3) _________________________________________= indicates the critical temperature and critical pressure above which a substance cannot exist in the __________________state no matter what pressure is applied

4) What is the triple point of water? ____________________________

5) What phase of matter would water be in at 1 atm and 375°C?_______________________

6) What phase of matter would water be in at 0.75 atm and 50°C?_______________________

Phase Diagram of Water

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Liquids & Phase Changes Review Worksheet

1) Describe how liquid particles are different from solid particles? 2) ______________________ is the spontaneous mixing of two or more substances.

3) Describe the general volume and shape of a liquid and use KMT to explain why a liquid exhibits these qualities.

4) Arrange the following in order of increasing viscosity at room temperature: tree sap, water, olive oil.

________________________________________

5) What is surface tension?

a. What are two examples of surface tension? 6) ____________________________ is the most abundant liquid.

7) Why water is considered a polar molecule? 8) Explain why the solid state of water (ice) is less dense than the liquid state. 9) ___________________________ is the transitioning from one state of matter to another.

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10) What can cause a phase change of matter? 11) What happens to the temperature of substance during a phase change?

a. Explain why.

12) Most solids shrink in size when frozen. What substance is an exception and actually expands? ___________

13) TRUE or FALSE: The temperature at which a substance freezes is lower than the temperature at which it melts.

a. Why?

14) Freezing occurs when energy is (absorbed OR released).

15) Condensation occurs when energy is (absorbed OR released).

16) Evaporation occurs when energy is (absorbed OR released).

17) Name each of the following changes of state:

a) liquid to gas ____________________ d) solid to liquid __________________ b) gas to liquid ____________________ e) gas to solid ____________________ c) solid to gas ____________________ f) liquid to solid __________________

18) What is the difference between the intermolecular forces during melting and freezing? Explain why.

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19) How are boiling and evaporation alike? 20) How are boiling and evaporation different?

21) Which would you expect to be more volatile, water or rubbing alcohol? Explain.

a. Which would boil first?________________________

22) _________________________________ is the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature.

23) How does a substance evaporate, if equilibrium vapor pressure is high? _________________________ a. Explain using KMT.

24) How does a substance evaporate, if equilibrium vapor pressure is low? _____________________________

a. Explain using KMT. 25) What is the normal boiling point of water? ______________________

26) When does a liquid’s boiling point occur?

27) What happens to the boiling point of liquids on top of Mt. Everest? Why?

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28) ______________________________________ is a dynamic condition in which two opposing physical or chemical changes occur at equal rates in a given closed system.

29) Describe a liquid-vapor system at equilibrium. (Don’t forget the particles.)

30) What is Le Chatelier’s principle?

a. Describe the equilibrium that exists in an inflated balloon. How does pressing on a balloon to decrease its size demonstrate Le Chatelier’s principle?

Answer the following questions using this chemical equation:

C(s) + H2O(g)

CO(g) + H2(g)

b. If the concentration of C was increased, the system would shift to the ________

c. If the concentration of CO was increased, the system would shift to the __________

d. If the concentration of H2 was decreased, the system would shift to the __________

31) A ________________________ is a graph of pressure versus temperature that shows which phase a substance exists in under different conditions of temperature and pressure.

32) The _________________________ indicates the temperature and pressure conditions at which the solid, liquid, and gas (vapor) of a substance can coexist at equilibrium.

33) Use the phase diagram below to answer the following questions:

a. The area on the graph that represents the gas phase is: ______

b. The area on the graph that represents the liquid phase is:______

c. The area on the graph that represents the solid phase is:______

d. When does the triple point occur? _________________________________

e. What happens to a substance as you move from point A to point B?____________________________

f. What happens to a substance as you move from point C to point A?________________________________

g. What happens to a substance as you move from point B to

point C? ______________________________

h. What phase of matter would this substance be in at 110°C and 0.5atm? ______________

i. What phase of matter would this substance be in at 50°C and 1.5atm? ______________

A. B

.

C.

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Unit Learning Map (6 days): Liquids & Phase Changes Mrs. Hostetter

Unit Essential Question(s): Optional Instructional Tools:

Guided Notes Demos: surface tension, volatile liquids Lab Materials: Cold Boil Lab Le Chat. Lab

How can you describe several properties of liquids using KMT (kinetic molecular

theory)?

Liquids Phase changes

1) How can you describe particle spacing and motion of a liquid?

1) What can cause a phase change of matter?

2) How can you describe a liquid-vapor system at equilibrium.

Diffusion Viscosity Surface tension Capillary action

Phase change Melting Freezing Sublimation Deposition Vaporization Condensation Vapor Closed System Open system Evaporation Volatile Liquid Nonvolatile liquid Equilibrium Vapor pressure Boiling point Le Chatelier’s Principle Phase Diagrams Triple Point

Vocabulary: Vocabulary:

Vocabulary: Vocabulary:

Lesson Essential Questions: Lesson Essential Questions: Lesson Essential Questions: Lesson Essential Questions:

Concept Concept Concept Concept

Class: Academic Chemistry B -PA Standard: Explain the relationship between the physical properties of a substance and its molecular or atomic structure.

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Liquids & Phase Changes Vocabulary:

1) Diffusion = the spontaneous mixing of two or more substances

2) Viscosity = resistance of a liquid to flow

3) Surface Tension = The energy required to increase the surface area of a liquid by a given amount; results from an uneven distribution of attractive forces.

4) Capillary action = liquids ability to flow up thin tubes; going against gravity

5) Phase change = transitioning from one state of matter to another.

6) Melting = as temp increases, the particles collide with each other more often and with a greater force so they move further apart (less intermolecular forces); the ordered arrangement of the solid state breaks down—solid has melted!

7) Freezing = in the liquid state there will be a temp. (and pressure) at which average energy of the particles become low enough that attractive forces will hold the particles together (increasing the intermolecular forces) in an orderly arrangement. The particles settle into an order arrangement and form a solid—liquid freezes!

8) Melting = Solid →Liquid; heat energy absorbed

9) Sublimation = Solid →Gas; heat energy absorbed

10) Freezing = Liquid → Solid; heat energy released

11) Vaporization = Liquid → Gas; heat energy absorbed

12) Condensation = Gas →Liquid; heat energy released

13) Deposition = Gas → Solid; heat energy released

14) Vapor = gas phase of a substance that is normally a SOLID or LIQUID at room temperature

15) Closed system = system in which matter cannot enter and leave the system (but energy can enter and leave)

16) Open system = system in which matter can enter and leave the system (also energy can enter and leave)

17) Evaporation = the process by which particles escape from the surface of a non-boiling liquid and enter the gas state

18) Volatile Liquid = a liquid that will evaporate readily and have lower boiling points

19) Nonvolatile Liquid = a liquid that will evaporate slowly

20) Equilibrium Vapor Pressure = the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature

21) Boiling = the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point.

22) Boiling Point = temperature at which equilibrium vapor pressure EQUALS atmospheric pressure

23) Le Chatelier’s Principle = When a system at equilibrium is disturbed by application of a stress, it attains a new equilibrium position that minimizes the stress

24) Phase Diagram = a graph of pressure versus temperature that shows which phase a substance exists in under different conditions of temperature and pressure.

25) Triple Point = indicates the temperature and pressure conditions at which the solid, liquid, and gas (vapor) of a substance can coexist at equilibrium