[ANSWER KEY ]
Review Chemistry Unit 11: States of Matter
1.
size
attractions
List the main parts of Kinetic-Molecular Theory (KMT) relating to each characteristic of gas particles:
a) gas particles have no significant volume (are tiny) compared to the great distance between them
b) gas particles have no significant attractive forces because they are so far apart______________
motion
c) gas particles are in constant, random motion_________________________________________
collisions
d) all collisions between gas particles are perfectly elastic (transfer KE without loss)____________
energy
2.
e) the average kinetic energy of gas particles in a sample is directly proportional to temperature_
List the 3 states of water in order of decreasing kinetic energy. (highest to lowest)
1) Gas
2) Liquid
3) Solid
3.
What happens to the kinetic energy of a liquid as it is heated? increases
4.
Define temperature. measure of average kinetic energy of particles of a substance.
avg. KE of a substance is proportional to the temperature
5.
Which has particles that are moving at 0oC? (circle all that are correct)
A. solid iron
B. liquid iodine
C. ammonia vapor
D. hydrogen gas
Which has the greatest average kinetic energy?
A. nitrogen gas at –50 C
B. neon gas at 20 C
C. CH3CH2OH vapor at 25 C
D. H2O vapor at 100 C
Choice _D_ because the higher temperature is directly proportional to higher avg KE
of a gas regardless of the chemical formula of the gas.
6.
What is the temperature at which there is absolutely NO motion of particles?
It’s called
absolute zero
at ___0__ K or –273 oC.
1
7.
Why are gases compressible, but liquids and solids are not? b/c of the great amount of
space between the particles (they to be pushed closer together)__________
8.
Consider the simple water cycle diagram below. Group the phase changes by heat energy
absorbed or released, by interparticle space, and by intermolecular attractions in the boxes.
condensation
absorbs energy
releases energy
melting
vaporization
sublimation
freezing
condensation
deposition
more space
between molecules
less space
between molecules
melting
vaporization
sublimation
freezing
condensation
deposition
less attraction
between molecules
more attraction
between molecules
melting
vaporization
sublimation
freezing
condensation
deposition
melting
evaporation
freezing
deposition
sublimation
9.
During each of the phase changes listed in #8, the temperature of the water will remain constant
because its potential energy is changing while its average kinetic energy is constant.
2
H-bond
10. Describe how a hydrogen bond forms between two molecules.
An electron deficient H atom bonded to a very electronegative atom (N, O, or F) is
attracted to an N, O, or F atom on a nearby molecule.
11. The strong attractions between polar water molecules cause water to have which of the
following properties: (circle all that apply)
A. greater surface tension
B.
C.
D.
E.
higher density liquid than solid (ice)
greater attraction to nonpolar molecules
higher boiling point
higher temperature
S
H2S
H
H2O
H
12. Hydrogen sulfide (H2S) boils at –60oC. Even though water is a smaller molecule that
should become a gas more easily than H2S, water doesn’t boil until it reaches 100oC.
Why are water molecules so difficult to separate from liquid phase to form a gas?
The H-bonds between water molecules are stronger intermolecular attractions than the
dipole-dipole forces of H2S). The stronger attractions require more energy to be overcome.
13. Stronger intermolecular attractions cause liquids to have _____________ boiling points and
cause solids to have ______________ melting points.
A.
B.
C.
D.
lower
lower
higher
higher
, lower
, higher
, lower
, higher
3
14. Identify which of the following changes involves the breaking of intramolecular bonds,
and which involve the breaking of intermolecular attractions? (circle one for each)
A. H2O(s)  H2O(l)
intramolecular bonds or intermolecular attractions
B. Fe2O3(s)  2 Fe(s) + 3 O2(g)
intramolecular bonds or intermolecular attractions
C. F2(g)  2 F(g)
intramolecular bonds or intermolecular attractions
D. NH3(l)  3 H2(g) + N2(g)
intramolecular bonds or intermolecular attractions
15. Warm water vapor from the air condenses onto a glass of cold ice water.
This happens when the water vapor __________ heat to/from the glass
causing the glass to become ___________.
A. releases/to , warmer
B.
releases/to , cooler
C. absorbs/from , warmer
D. absorbs/from , cooler
16.
Heat is energy that is transferred due to a difference in temperature
17.
Describe the direction of heat flow when a hot rock at 105 C is placed into cool water at 18 C.
o
o
Heat flows from the rock to the water making the
rock cooler and the water warmer.
18.
o
Describe the direction of heat flow when a piece of solid water (ice) at 0 C is held in
o
your hand at 37 C.
Heat flows from the hand to the water (ice) making
the hand cooler and water warmer.
4
For #19-21, refer to the heating curve below for water as heat is added at a constant rate.
E
Temperature ( C)
D
o
C
B
A
Heat added
19. Circle which phase(s) of water exist(s) in each section of the heating curve.
section A.
solid liquid gas
section B.
solid liquid gas
section C.
solid
liquid gas
section D.
solid
liquid gas
section E.
solid
liquid gas
20. Circle which type of energy is increasing in the sample during each section as heat is being added.
section A.
kinetic
potential
section B.
kinetic
potential
section C.
kinetic
potential
section D.
kinetic
potential
section E.
kinetic
potential
21. If heat were removed instead of added, the process occurring in section D would be _____.
A.
B.
C.
D.
vaporization
freezing
condensation
NONE of the above
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