#### Chapter 13&15 Physics

A bimetallic strip, consisting of metal G on the top and metal H on the bottom, is rigidly attached to a wall at the left. (See Fig. 13-1.) The coefﬁcient of linear thermal expansion for metal G is greater than that of metal H. If the strip is uniformly heated, it will

curve downward.

When the engine of your car heats up, the spark plug gap will

increase

Consider a flatsteel plate with a hole through its center as shown in Fig. 13-2. When the plate's temperature is increased, the hole will

always expand.

The coefficient of linear expansion for aluminum is1.8 x10-6(C°)-1. What is its coefficient of volume expansion?

5.4x10-6(C°)-1

The surface water temperature on a large, deep lake is 3°C. A sensitive temperature probe is lowered several meters into the lake. What temperature will the probe record?

a temperature warmer than 3°C

Which temperature scale never gives negative temperatures?

Kelvin

Which two temperature changes are equivalent?

1C° =1K

The temperature in your classroom is approximately

295K

A container of an ideal gas at 1 atm is compressed to one-third its volume, with the temperature held constant. What is its final pressure?

3 atm

If the pressure acting on an ideal gas at constant temperature is tripled, its volume is

reduced toone-third.

According to the ideal gas Law, PV = constant for a given temperature. As a result, an increase in volume corresponds to a decrease in pressure. This happens because the molecules

strike the container wall less often.

The number of molecules in one mole of a substance

isthesameforallsubstances.

A container holds N molecules of an ideal gas at a given temperature. If the number of molecules in the container is increased to 2N with no change in temperature or volume, the pressure in the container

doubles

Both the pressure and volume of a given sample of an ideal gas double. This means that its temperature in Kelvin must

The temperature of an ideal gas increases from 2°C to 4°C while remaining at constant pressure. What happens to the volume of the gas?

It increases slightly.

A mole of diatomic oxygen molecules and a mole of diatomic nitrogen molecules at STP have

the same number of molecules.

Consider two equal volumes of gas at a given temperature and pressure. One gas, oxygen, has a molecular mass of 32. The other gas, nitrogen, has a molecular mass of 28. What is the ratio of the number of oxygen molecules to the number of nitrogen molecules?

1:01

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

the temperature of the gas.

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?

It does not change.

A sample of an ideal gas is heated and its Kelvin temperature doubles. What happens to the average speed of the molecules in the sample?

none of the above

The absolute temperature of an ideal gas is directly proportional to which of the following?

kinetic energy

In order to double the average speed of the molecules in a given sample of gas, the temperature (measured in Kelvin) must

)increase by a factor of square root two of its original value.

The process shown on the T-V graph is an

isothermal compression

In an isothermal process, there is no change in

temperature

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

none of the above

A gas is expanded to twice its original volume with no change in its temperature. This process is

isothermal

An ideal gas is compressed isothermally from 30 L to 20 L. During this process, 6.0 J of energy is expended by the external mechanism that compressed the gas. What is the change of internal energy for this gas?

zero

An ideal gas is compressed to one-half its original volume during an isothermal process. The ﬁnal pressure of the gas

increases to twice its original value.

An ideal gas is expanded isothermally from 20 L to 30 L. During this process, 6 J of energy is expended by the external mechanism that expanded the gas. Which of the following statements is correct?

6 J of energy flow form the surrounds into the gas

A gas is quickly compressed in an isolated environment. During the event, the gas exchanged no heat with its surroundings. This process is

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

Q=0

A monatomic ideal gas is compressed to one-half its original volume during an adiabatic process. The ﬁnal pressure of the gas

increases to more than twice its original value.

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?

the He

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?

the He

The process shown on the PV diagram is an

isobaric expansion

In an isobaric process, there is no change in

pressure

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

none of the above

A gas is allowed to expand at constant pressure as heat is added to it. This process is

isobaric

Ten joules of heat energy are transferred to a sample of ideal gas at constant pressure. As a result, the internal energy of the gas

increases by less than 10 J.

The process shown on the PV diagram is

isochoric

) In an isochoric process, there is no change in

volume

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

W = 0

A gas is conﬁned to a rigid container that cannot expand as heat energy is added to it. This process is

isochoric

Ten joules of heat energy are transferred to a sample of ideal gas at constant volume. As a result, the internal energy of the gas

increases by 10 J.

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

Yes; this will happen naturally.

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

Yes, but work will have to be done.

A gas is taken through the cycle illustrated here. During one cycle, how much work is done by an engine operating on this cycle?

3PV

) The efﬁciency of a heat engine is deﬁned as the ratio of

the work it does to the heat input at the high temperature.

If the theoretical efﬁciency of a Carnot engine is to be 100%, the heat sink must be

at absolute zero.

A Carnot cycle consists of

) The coefﬁcient of performance (COP) of a refrigerator is deﬁned as the ratio of

the heat removed from the inside to the work done to remove the heat.

The coefﬁcient of performance (COP) of a heat pump is deﬁned as the ratio of

the heat delivered to the inside to the work done to move the heat.

When water freezes, the entropy of the water

decreases.

According to the second law of thermodynamics, for any process that may occur within an isolated system, which one of the choices applies?

Both A and B are possible.

The second law of thermodynamics leads us to conclude that

disorder in the universe is increasing with the passage of time.

Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, the average molecular kinetic energy of oxygen, compared to hydrogen

is the same.

Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, how do their average molecular speeds compare? The oxygen molecules are moving

at 1/4 the speed

A ﬁxed container holds oxygen and helium gases at the same temperature. Which one of the following statements is correct?

The helium molecules have the greater speed

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?

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

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?

The helium molecules do because they are less massive.

The three phases of matter can exist together in equilibrium at the

triple point