AnswersEO Chemistry 7320BUnit Test

Unit Test — Unit test Answers

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1
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Why do amorphous solids not have a long-range order in the arrangement of their particles?

A
Their formation involves very rapid cooling.
B
They do not have enough particles.
C
Their particles eventually change positions.
D
Their particles always stay in the same positions.
2
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Consider the temperature versus time graph below.At what temperature is the substance a heated gas?

Question illustration
A
at 100°C
B
below 0°C
C
above 100°C
D
between 0°C and 100°C
3

The diagrams show gases that are stored in two separate but similar containers.If both gases are at the same temperature, which one has the greater pressure?

Question illustration
A
gas 1 because the particles are moving much faster
B
gas 1 because it has fewer particles that are close together
C
gas 2 because it has more particles that are colliding
D
gas 2 because the particles have more space between them
4

Which sequence represents the relationship between pressure and volume of an ideal gas as explained by the kinetic-molecular theory?

A
more gas particles more collisions higher pressure
Option A
B
smaller volume crowded particles less collisions lower pressure
Option B
C
smaller volume crowded particles more collisions higher pressure
Option C
D
more gas particles more kinetic energy more volume higher pressure
Option D
5

In the diagram below, particles of the substance are moving from the liquid phase to the gas phase at the same rate as they move from the gas phase to the liquid phase.The gas and liquid are at

Question illustration
A
equilibrium.
B
a high vapor pressure.
C
a low vapor pressure.
D
zero vapor pressure.
6

Which is a postulate of the kinetic-molecular theory?

A
Gas particles have a small volume relative to the spaces between them.
B
Gas particles have a large volume relative to the spaces between them.
C
Gas particles are very small in size and always move slowly.
D
Gas particles are very large in size and always move slowly.
7

A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia?Use .

Question illustration
A
0.27 atm
B
0.36 atm
C
0.54 atm
D
0.90 atm
8

Which sequence describes the result of increasing the temperature of a gas in a container?

A
higher kinetic energy ® greater collision force ® higher pressure
B
lower kinetic energy ® greater collision force ® higher pressure
C
higher kinetic energy ® lower collision force ® lower pressure
D
lower kinetic energy ® lower collision force ® lower pressure
9

Which best characterizes a crystal?

A
a number of high speed particles moving randomly
B
a dense substance that is hard and incompressible
C
a high-energy state of matter made up of a swirling, ionized gas
D
a loose association of particles moving past one another
10

According to the kinetic-molecular theory, what happens to a liquid when it is transferred from one container to another?

A
The volume and the shape stay the same.
B
The volume increases to fill the new container, but the shape stays the same.
C
The volume stays the same, but the shape changes to fit the new container.
D
The volume and the shape change to fill the new container.
11

Which units of pressure are equivalent and require no conversion of the value?

A
mmHg and atm
B
kPa and Pa
C
mmHg and torr
D
atm and kPa
12

Which statement describes a limitation of the kinetic-molecular theory for a gas?

A
The theory assumes that particles do not experience intermolecular forces.
B
The theory states that pressure is inversely proportional to volume.
C
The theory assumes that particles are in random and continuous motion.
D
The theory states that pressure increases with temperature.
13

A gaseous substance turns directly into a solid. Which term describes this change?

A
deposition
B
evaporation
C
melting
D
sublimation
14

Why does changing the volume of a container change the pressure of the gas in it?

A
Changing the volume reduces the number of molecules so they hit the walls of the container less often.
B
Changing the volume reduces the force with which the molecules hit the walls of the container.
C
Changing the volume increases the speed of the molecules so they hit the walls of the container more often.
D
Changing the volume increases the area that the molecules collide with so the force is spread over a larger area.
15

Which statement best compares the melting point of butane (C4H10) with that of octane (C8H18)?

A
The melting points of both substances are identical.
B
The melting point is higher for butane.
C
The melting point is higher for octane.
D
The comparison of melting points cannot be made.

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