Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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Which
of the following statements is not an assumption in the kinetic model of gases? a. | Gas particles
are assumed to have zero volume | c. | Gas particles
move in a straight line unless they have a collision. | b. | Gas particles
have weak forces of attraction between them | d. | Kinetic energy is conserved in the collisions. The collisions
are perfectly elastic | | | | |
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2.
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The
effect of increasing temperature on the Maxwell speed distribution is: a. | The average
speed decreases. | c. | The distribution
becomes narrower and the average speed increases. | b. | The distribution
becomes broader and the most probable speed moves to a lower value. | d. | The distribtion becomes broader and the average speed
increases | | | | |
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3.
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The
effect of increasing molar mass on the Maxwell speed distribution is: a. | The average
speed increases | c. | The distribution
becomes narrower and the speed increases. | b. | The distribution becomes
narrower. | d. | There is no
effect. | | | | |
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4.
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In
the Maxwell-Boltzman distribution of energies: a. | Kinetic energy values are normally plotted on the vertical
y-axis. | c. | The distribution
becomes narrower as the temperature increases | b. | The average
kinetic energy is slighty less than the most probable energy value. | d. | The most probable energy value is at the maximum of the
distribution curve. | | | | |
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5.
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What
changes occur when ice at its melting point is converted to liquid water?
I. Movement of
the molecules increases
II. distance between molecules increases. a. | I
only | c. | Both I and
II | b. | II
only | d. | Neither I and
II | | | | |
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6.
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All
of the following are characteristic properties of gases EXCEPT
a. | they can expand
without limit | c. | they are easily
compressed | b. | they diffuse readily | d. | they have high densities | | | | |
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7.
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The
boiling points of four hydrocarbons are given. Which pair will mix most easily at the
temperature specified?
Tb/k
Tb/k
cyclohexane
354
cyclooctane
421
cycloheptane
392
cyclononane 444 a. | cyclohexane and
cycloheptane at 380 K | c. | cyclooctane and
cyclononane at 460 K | b. | cycloheptane and cycloocatane at 390
K | d. | cyclononane and
cyclohexane at 420 K | | | | |
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8.
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235U and 238U are seperated by allowing uranium hexafluoride,
UF6, to diffuse through a series of tiny holes. This process works because the molecules
of UF6 that contain 235U and 238U have different a. | volumes | c. | chemical
properties | b. | shapes | d. | speeds | | | | |
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9.
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1.0 g
of liquid H2O has a volume of 1.0 cm3 but a volume of slightly more than 1
dm3 when it is converted to vapour at the same temperature. This volume change is best
attributed to a. | an increase in
the size of the molecules | c. | the higher
kinetic energy of the molecules | b. | the greater distance between the
molecule | d. | the presence of
more molecules due to the conversion of H2O to H2 and
O2. | | | | |
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10.
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Which
of the following best accounts for the observation that gases are easily compressed. a. | Gas molecules
have negligible attractive forces for one another | c. | The average energy of the molecules in a gas is proportional to
the absolute temperature of the gas. | b. | The volume occupied by the gas is much greater than that
occupied by the molecules | d. | The collisions
between gas molecules are elastic. | | | | |
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11.
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Equal
volumes of different ideal gases at the same temperature and pressure must contain a. | the same number
of atoms | c. | the same amount
of each gas | b. | one mole of each gas | d. | 6.022 x 1023 particles of each
gas | | | | |
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12.
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All
of the collowing statements are correct about the behaviour of an ideal gas except a. | it expands on
heating | c. | the average
energy of the particles doubles when the absolute temperature doubles | b. | the particles in
it are in continuous random motion | d. | The volume increases as the pressure applied to it
increases | | | | |
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13.
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A 1.0
dm3 sample of gas is heated from 27ºC to 54ºC at constant pressure. The colume
of the gas will a. | increases to
about 1.1 dm3 | c. | decreases to
about 0.9dm3 | b. | increases to about 2.0
dm3 | d. | decreases to
about 0.5 dm3 | | | | |
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14.
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The
temperature (in K) is doubled for a sample of gas in a flexible container while the pressure on it is
doubled. The final volume of the gas compared with initial volume will be: a. | the
same | c. | four times as
large | b. | twice as large | d. | half as large | | | | |
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15.
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Seperate samples of two gases, each containing a pure substance, are found to have the
same density under the same conditions of temperature and pressure. Which statement about these two
samples must be corrected. a. | they have the same volume | c. | there are equal numbers of moles of gas in the two
samples | b. | they have the same relative molecular
mass | d. | they condense at
the same temperature. | | | | |
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16.
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Which
expression repersents the density of a gas sample of relative molar mass, Mr, at
temperature T, and pressure, P?
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17.
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A 250
cm3 sample of an unknown gas has a mass of 1.42 g at 35ºC and 0.85 atmospheres, Which
expression gives its molar mass, Mr? (R=82.05cm3 atm K-1
mol-1)
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18.
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Which
graphs show the energy distribution for the particles of a gas when the temperature is increased from
T1 to T2?
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19.
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Which
one of the following statements about the properties or behavior of gases is
correct?
a. | Gas molecules increase in size when they are
heated. | c. | The attraction
between the molecules in a gas increases with increasing temperature. | b. | The distance
between the molecules in a gas is much larger than the molecule’s
size. | d. | Heavier gas
molecules diffuse more quickly than lighter ones. | | | | |
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20.
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A
child’s balloon contains a certain volume of helium at room temperature and pressure.
Under which change of conditions will the volume become greatest? a. | Higher
temperature and higher pressure.
| c. | Lower temperature and higher
pressure.
| b. | Higher temperature and lower
pressure. | d. | Lower
temperature and lower pressure.
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21.
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A
flask contains a liquid and its vapour in equilibrium at the boiling point. In what way(s) do
the molecules in the liquid differ from those in the vapour?
I. The distance between the
molecules
II. The average speed of the
molecules
a. | I only
| c. | Both I and
II | b. | II
only | d. | Neither I nor
II | | | | |
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22.
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Equal
volumes of ammonia and nitrogen gas at the same temperature and pressure will have the
same
a. | density. | c. | number or
molecules. | b. | numbre of atoms. | d. | percentage of nitrogen. | | | | |
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23.
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In a
solid such as iodine, I2(s), the intermolecular bonding forces which cause the substance
to remain in the solid state are
a. | covalent bonds | c. | metallic bond | b. | ionic bonds
| d. | van der Waals'
forces. | | | | |
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24.
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A
sealed 250 dm3 vessel contains 1 mole of hydrogen, 2 moles of nitrogen and 3 moles of
argon gas. The average velocities of the molecules are
a. | the same for all
the molecules | c. | largest in the
case of argon atoms | b. | largest in the case of hydrogen
molecules | d. | in the ratio of
1:2:3 for hydrogen, nitrogen and argon | | | | |
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25.
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When
a gas is heated there is a change in volume. Which of the following statements correctly
describes and explains the change?
a. | The volume
increases because the molecules become larger. | c. | The volume decreases because the molecules become
smaller. | b. | The volume increases because the molecules have more kinetic
energy. | d. | The volume
decreases because molecules bond more tightly at higher temperatures | | | | |
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26.
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At a
given temperature molecules with comparable masses will diffuse
a. | faster in gases than in liquids and faster in liquids than in
solids. | c. | faster in gases,
but equally fast in liquids and solids. | b. | at the same rates in all three
phases | d. | equally fast in
gases and liquids, but faster than in solids. | | | | |
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27.
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The
greatest volume would be occupied by a given quantity of gas at
a. | low temperature
and low pressure. | c. | high temperature
and high pressure. | b. | low temperature and high
pressure. | d. | high temperature
and low pressure. | | | | |
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28.
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Which
of the following occurs when a solid is converted to a gas?
I. The distances between the molecules
increase.
II. The sizes of the molecules increase.
a. | I
only | c. | Both I and
II | b. | II
only | d. | Neither I nor
II | | | | |
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29.
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Under
which conditions will a gas sample occupy the smallest volume?
a. | low T and low
P | c. | high T and low
P | b. | low T and high
P | d. | high T and high
P | | | | |
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30.
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Which
one of the following gases would occupy the largest volume at 25°C and 1.0 atm
pressure?
a. | 100 g
CH4 | c. | 100 g CO | b. | 100 g
CO2 | d. | all of the gases
would have the same volume | | | | |
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31.
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Which
of the following statements is (are) true about the molecules of a certain substance which is
found in both the liquid and gaseous states at room temperature?
I. The distance between
the molecules in the gas is much greater than the size of the
molecules.
II. The
distance between the molecules in the liquid is much greater than the size of the
molecules.
a. | Only I is
true. | c. | Both I and II
are true. | b. | Only II is true. | d. | Neither I nor II is true | | | | |
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32.
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A
small amount of heat is added to a solid at its melting point. Which one of the following
statements best describes what happens?
a. | The temperature remains constant as the solid
melts. | c. | The temperature
rises as the solid melts.
| b. | The temperature rises before the solid
melts. | d. | The temperature
decreases as the solid melts. | | | | |
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