Midterm 2

Question 1

What would be the greatest effect of the finite size of molecules on the ideal gas law?

Answer 1

At high densities, the pressure would be less than that predicted by the ideal gas law.

Question 2

What would be the greatest effect on the ideal gas law if there is a slight attractive force between the molecules?

Answer 2

At low temperatures, the pressure would be less than that predicted by the ideal gas law.

Question 3

What would be the greatest effect on the ideal gas law if there is a slight repulsive force between the molecules?

Answer 3

At low temperatures, the pressure would be greater than that predicted by the ideal gas law.

Question 4

The average molecular kinetic energy of a gas can be determined by knowing only the – of the gas.

Answer 4

temperature

Question 5

A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample

Answer 5

It does not change.

Question 6

A container is filled with a mixture of helium and oxygen gases. A thermometer in the container indicates that the temperature is 22°C. Which gas molecules have the greater average kinetic energy?

Answer 6

It is the SAME for both because the temperatures are the same.

Question 7

A container is filled with a mixture of helium and oxygen gases. A thermometer in the container indicates that the temperature is 22°C. Which gas molecules have the greater average speed?

Answer 7

The helium molecules because they are less massive.

Question 8

Phase change occur as the temperature

Answer 8

remains the same

Question 9

The point in the phase diagram where the fusion curve, the vapor pressure curve, and the sublimation curve join is called the

Answer 9

triple point

Question 10

The point in the phase diagram where the vapor pressure curve ends is called the

Answer 10

critical point

Question 11

When a solid melts, heat energy – the substance

Answer 11

enters

Question 12

When a liquid freezes, heat energy – the substance

Answer 12

leaves

Question 13

By what primary heat transfer mechanism does one end of an iron bar become hot when the other end is
placed in a flame?

Answer 13

conduction

Question 14

The type of heat transfer that occurs between a stove and a pot placed on it is

Answer 14

conductive

Question 15

The type of heat transfer that occurs between the radiator of a car and the atmosphere, when the car is in
motion, is principally

Answer 15

convective

Question 16

The type of heat transfer that occurs between warm food and the air in the room is principally

Answer 16

convective

Question 17

Convection can occur

Answer 17

only in liquids and gases

Question 18

The process whereby heat flows in the absence of any medium is referred to as

Answer 18

radiation

Question 19

The process whereby heat flows by the mass movement of molecules from one place to another is referred to
as

Answer 19

convection

Question 20

The process whereby heat flows by means of molecular collisions is referred to as

Answer 20

conduction

Question 21

Consider two cylinders of gas identical in all respects except that one contains O2 and the other He. Both hold the same volume of gas at STP and are closed by a movable piston at one end. Both gases are now
compressed adiabatically to one-third their original volume. Which gas will show the greater pressure increase?

Answer 21

the He

Question 22

Consider two cylinders of gas identical in all respects except that one contains O2 and the other He. Both hold the same volume of gas at STP and are closed by a movable piston at one end. Both gases are now
compressed adiabatically to one-third their original volume. Which gas will show the greater temperature increase?

Answer 22

the He

Question 23

An ideal gas starts in state A at temperature T. The gas expands to new volume V by an adiabatic process
and its final temperature is T’. What is the relationship between T and T’?

Answer 23

T > T’

Question 24

When a gas expands adiabatically,

Answer 24

the internal energy of the gas decreases

Question 25

During which type of process applied to an ideal gas is there no change in internal energy of the gas?

Answer 25

isothermal

Question 26

During which type of process applied to an ideal gas is there no heat added to the gas?

Answer 26

adiabatic

Question 27

During which type of process applied to an ideal gas is there no work done by the gas?

Answer 27

isochoric

Question 28

When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an isochoric process,

Answer 28

W = 0

Question 29

When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an adiabatic process,

Answer 29

Q = 0

Question 30

When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an isothermal process,

Answer 30

ΔU = 0

Question 31

Is it possible to transfer heat from a cold reservoir to a hot reservoir?

Answer 31

Yes, but work will have to be done

Question 32

The internal energy of an ideal gas is changed by adding heat Q to the system and also by doing work W on the gas. What is the change in internal energy of the gas?

Answer 32

Q + W

Question 33

A chunk of ice (T = -20°C) is added to a thermally insulated container of cold water (T = 0°C). What happens in the container?

Answer 33

Some of the water freezes and the chunk of ice gets bigger

Question 34

The heat required to change a substance from the liquid to the vapor state is referred to as the

Answer 34

hear of vaporization

Question 35

The heat required to change a substance from the solid to the liquid state is referred to as the

Answer 35

heat of fusion

Question 36

A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in thermal contact. The specific heat capacity of aluminum is more than double that of copper. Which object experiences the greater temperature change during the time the system takes to reach thermal equilibrium?

Answer 36

it is impossible to tell without knowing the masses

Question 37

A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in thermal contact. The specific heat capacity of aluminum is more than double that of copper. Which object experiences the greater magnitude gain or loss of heat during the time the system takes to reach thermal equilibrium?

Answer 37

neither; both experience the same size gain or loss of heat

Question 38

It is a well-known fact that water has a higher specific heat capacity than iron. Now, consider equal masses of water and iron that are initially in thermal equilibrium. The same amount of heat, 30 calories, is added to each. Which statement is true?

Answer 38

They are no longer in thermal equilibrium; the iron is warmer.

Question 39

A cup of water is scooped up from a swimming pool of water. Compare the temperature T and the internal energy U of the water, in both the cup and the swimming pool.

Answer 39

TPool is equal to TCup, and UPool is greater than UCup

Question 40

closed system in which NO ENERGY in any form is transferred

Answer 40

isolated system

Question 41

NO MASS enters or leaves but energy may be exchanged

Answer 41

closed system

Question 42

mass and energy transfer

Answer 42

Open system