Deck 5: Matter and Heat

Question 1

The pressure at the bottom of a barrel filled with liquid does not depend on the

A)acceleration of gravity.
B)liquid density.
C)height of the liquid.
D)area of the liquid surface.

Answer 1

area of the liquid surface.

Question 2

In order for an object to sink when placed in water, the object's average density must be

A)less than that of water.
B)equal to that of water.
C)more than that of water.
D)Any of these choices are correct, depending on the object's shape.

Answer 2

more than that of water.

Question 3

A Celsius thermometer and an absolute thermometer are used to measure the temperature of the same gas sample.The readings on the thermometers are respectively T_C and T_K.Which is correct?

A)T_C is smaller than T_K.
B)T_C is larger than T_K.
C)T_C is equal to T_K.
D)Any of these choices could be correct, depending on the gas temperature.

Answer 3

T_C is smaller than T_K.

Question 4

Which of the following formulas relating temperatures on the Celsius and Fahrenheit scales is correct?

A)T_c = (5/9)(T_F - 32 ^$\circ$ )
B)T_c = (5/9)(T_F + 32 ^$\circ$ )
C)T_c = (9/5)(T_F - 32 ^$\circ$ )
D)T_c = (9/5)(T_F + 32 ^$\circ$ )

Question 5

Which of the following is not true of molecular motion in a gas?

A)There is no order in the motion.
B)There is no uniformity of speed or direction.
C)There is a definite average speed at a given temperature.
D)There is a definite average direction of motion at a given temperature.

Question 6

The properties of several different materials are being compared.If the samples all have the same volume, the one with the greatest mass also has the greatest

A)density.
B)buoyancy.
C)pressure.
D)temperature.

Question 7

Which of the following formulas expresses the relationship between the pressure and absolute temperature of a gas sample whose volume is fixed?

A)
B)
C)
D)

Question 8

Which of the following quantities is independent of the size and shape of an object composed of a given material?

A)volume
B)mass
C)weight
D)density

Question 9

A typical metabolic rate while walking is

A)10 W.
B)50 W.
C)300 W.
D)1.2 kW.

Question 10

A cake of soap is placed in a bathtub sink.The buoyant force on the soap is

A)0.
B)less than its weight.
C)equal to its weight.
D)more than its weight.

Question 11

A barometer measures

A)atmospheric density.
B)atmospheric pressure.
C)water density.
D)water pressure.

Question 12

A thermometer calibrated in the Celsius scale and a thermometer calibrated in the Fahrenheit scale are used to measure the same temperature.The numerical reading on the Fahrenheit thermometer

A)is proportional to that on the Celsius thermometer.
B)is smaller than that on the Celsius thermometer.
C)is larger than that on the Celsius thermometer.
D)may be smaller or larger than that on the Celsius thermometer.

Question 13

The pressure on the bottom of an object inside a liquid is

A)less than the pressure on its top.
B)equal to the pressure on its top.
C)more than the pressure on its top.
D)Any of these choices, depending on the nature of the liquid.

Question 14

Of the substances below, the one with the highest specific heat is

A)water.
B)ice.
C)concrete.
D)gold.

Question 15

Of the following, a molecule is best described as

A)any very tiny particle.
B)the smallest particle found in nature.
C)the smallest particle of a substance that is representative of the substance.
D)the ultimate particle of which all matter is composed.

Question 16

Of these substances, the one with the lowest specific heat is

A)water.
B)ice.
C)concrete.
D)gold.

Question 17

Ice floats in water because

A)its density is less than that of water.
B)its specific heat is less than that of water.
C)it is a solid whereas water is a liquid.
D)it is colder than water.

Question 18

When heat is added to a body of matter, the resulting temperature increase does not depend upon

A)its mass.
B)its shape.
C)what kind of material it consists of.
D)whether it is in the solid, liquid, or gaseous state.

Question 19

The average pressure of the atmosphere at sea level corresponds to which one or more of the following?

A)101 Pa
B)101 kPa
C)98 kPa
D)15 lb/in²
E)Both B and D

Question 20

Molecules are, in general, farthest apart from one another in

A)gases.
B)liquids.
C)crystalline solids.
D)amorphous solids.

Question 21

In order to operate, a heat engine must have

A)either a hot or a cold reservoir.
B)both a hot and a cold reservoir.
C)a boiler.
D)a supply of fuel that can be burned, such as coal or oil.

Question 22

The work output of every heat engine

A)equals its heat intake.
B)equals the difference between its heat intake and heat exhaust.
C)depends only on its intake temperature.
D)depends only on its exhaust temperature.

Question 23

When a liquid becomes a vapor,

A)its temperature must decrease.
B)its temperature must increase.
C)it must absorb heat.
D)it must give off heat.

Question 24

When a gas is forced into a smaller volume without a change in temperature, its pressure increases because its molecules

A)strike the container walls more often.
B)strike the container walls at higher speeds.
C)strike the container walls with greater force.
D)have more energy.

Question 25

Molecular motion in a gas is the minimum possible at

A)0 ^$\circ$ F.
B)0 ^$\circ$ C.
C)0 K.
D)-273 K.

Question 26

The melting point of water is 0 ^$\circ$ C.Its freezing point is

A)slightly less than 0 ^$\circ$ C.
B)0 ^$\circ$ C.
C)slightly more than 0 ^$\circ$ C.
D)32 ^$\circ$ C.

Question 27

Heat transfer by convection occurs

A)only in liquids.
B)only in gases.
C)only in liquids and gases.
D)in liquids, gases, and solids.

Question 28

Radiation is emitted

A)only by liquids.
B)only by solids.
C)only by liquids and solids.
D)by liquids, solids, and gases.

Question 29

When a liquid freezes to become a solid,

A)its temperature rises.
B)its temperature falls.
C)it absorbs heat.
D)it gives off heat.

Question 30

The freezing point of a substance is always lower than its

A)melting point.
B)boiling point.
C)heat of fusion.
D)heat of vaporization.

Question 31

A sample of a gas is expanded to twice its original volume while its temperature is held constant.Relative to their original average energy, the new average energy of the molecules is

A)half as great.
B)the same.
C)twice as great.
D)four times as great.

Question 32

Heat transfer in a vacuum

A)can take place only by radiation.
B)can take place only by radiation and convection.
C)can take place by radiation, convection, and conduction.
D)cannot take place.

Question 33

The temperature of a gas sample in a rigid container is reduced.The pressure the gas exerts on the container walls decreases because

A)its molecules are in contact with the walls for briefer intervals.
B)its molecular masses decrease.
C)its molecules have lower average speeds and so strike the walls less often with less momentum.
D)its molecules lose less energy each time they strike the walls.

Question 34

Steam at 100 ^$\circ$ C is more dangerous than the same mass of water at 100 ^$\circ$ C because the steam

A)is less dense.
B)moves faster.
C)has a higher specific heat.
D)releases a great deal of heat when it condenses.

Question 35

Sublimation refers to

A)the vaporization of a solid without first becoming a liquid.
B)the melting of a solid.
C)the vaporization of a liquid.
D)the condensation of a gas into a liquid.

Question 36

Suppose there were molecules that had no attraction whatsoever for one another.A collection of such molecules would form a

A)gas.
B)liquid.
C)amorphous solid.
D)crystalline solid.

Question 37

The first law of thermodynamics is the same as the

A)second law of thermodynamics.
B)law of conservation of energy.
C)law of conservation of momentum.
D)first law of motion.

Question 38

The maximum possible efficiency of a heat engine

A)is 100%.
B)depends on the intake temperature.
C)depends on the difference between the exhaust and intake temperatures.
D)depends on the ratio between the exhaust and intake temperatures.

Question 39

The physics of a heat engine cannot be used to understand the operation of a

A)nuclear reactor.
B)heat pump.
C)refrigerator.
D)diesel engine.

Question 40

Heat transfer by conduction occurs

A)only in liquids.
B)only in solids.
C)only in liquids and solids.
D)in liquids, solids, and gases.

Question 41

The specific heat of ice is 2.1 kJ/kg ^$\circ$ C.When 50 kJ of heat is removed from 2 kg of ice initially at -5 ^$\circ$ C, the final temperature of the ice is

A)-6 ^$\circ$ C.
B)-11 ^$\circ$ C.
C)-12 ^$\circ$ C.
D)-17 ^$\circ$ C.

Question 42

The density of air is 1.3 kg/m³.The air in a room 5 m long, 4 m wide, and 2.5 m high has a mass of

A)0.26 kg.
B)6.5 kg.
C)38 kg.
D)65 kg.

Question 43

The density of brass is 8 *10³ kg/m³.The volume occupied by 320 g of brass is

A)0.038 cm³.
B)3.2 cm³.
C)38 cm³.
D)380 cm³.

Question 44

When 90 kJ is removed from a 2-kg copper bar, its temperature drops from 200 ^$\circ$ C to 85 ^$\circ$ C.The specific heat of copper is

A)0.16 kJ/kg ^$\circ$ C.
B)0.19 kJ/kg ^$\circ$ C.
C)0.23 kJ/kg ^$\circ$ C.
D)0.39 kJ/kg ^$\circ$ C.

Question 45

Ethanol boils at 172 ^$\circ$ F.The Celsius equivalent of this temperature is

A)64 ^$\circ$ C.
B)78 ^$\circ$ C.
C)140 ^$\circ$ C.
D)278 ^$\circ$ C.

Question 46

In an isolated system, entropy

A)cannot decrease.
B)must remain constant.
C)cannot increase.
D)may increase, decrease, or remain constant.

Question 47

The heat a refrigerator absorbs from its contents is

A)less than it gives off.
B)the same amount it gives off.
C)more than it gives off.
D)Any of these choices, depending on its design.

Question 48

A container holds 1 g of air at atmospheric pressure.When an additional gram of air is pumped into the container and there is no change in temperature, the new pressure is

A)0.5 atm.
B)1 atm.
C)2 atm.
D)4 atm.

Question 49

One liter of hydrogen gas at atmospheric pressure is allowed to expand to a volume of 3 liters with the temperature held constant.If the average speed of the hydrogen molecules was originally v, their new average speed is

A)v/9.
B)v/3.
C)v.
D)3 v.

Question 50

A temperature of 20 ^$\circ$ C is the same as

A)-20.9 ^$\circ$ F.
B)-6.4 ^$\circ$ F.
C)68 ^$\circ$ F.
D)94 ^$\circ$ F.

Question 51

An absolute temperature of 100 K is the same as a Celsius temperature of

A)-173 ^$\circ$ C.
B)32 ^$\circ$ C.
C)212 ^$\circ$ C.
D)373 ^$\circ$ C.

Question 52

The pressure on 100 liters of helium is increased from 100 kPa to 400 kPa.The new volume of the helium is

A)25 liters.
B)50 liters.
C)400 liters.
D)1600 liters.

Question 53

The specific heat of water is 4.2 kJ/kg ^$\circ$ C.How long will it take for a 2-kW heating element to raise the temperature of 30 kg of water from 20 ^$\circ$ C to 80 ^$\circ$ C?

A)6.3 min
B)15 min
C)63 min
D)84 min

Question 54

A 400-kg concrete block is 1 m long, 0.6 m wide, and 0.3 m high.Its density is

A)72 kg/m.
B)222 kg/m.
C)667 kg/m.
D)2222 kg/m.

Question 55

At which of the following Celsius temperatures will a Fahrenheit thermometer show the same reading in degrees?

A)-40 ^$\circ$ C
B)0 ^$\circ$ C
C)32 ^$\circ$ C
D)40 ^$\circ$ C

Question 56

A refrigerator

A)produces cold.
B)changes heat to cold.
C)causes heat to disappear.
D)removes heat from a region and carries it elsewhere.

Question 57

A 400-kg concrete block is 1 m long, 0.6 m wide, and 0.3 m high.It can exert three different pressures on a horizontal surface, depending on which face it rests on.The highest pressure is

A)0.7 kPa.
B)2.2 kPa.
C)13.1 kPa.
D)21.8 kPa.

Question 58

The entropy of a system is a measure of its

A)temperature.
B)heat content.
C)density.
D)disorder.

Question 59

The specific heat of water is 4.2 kJ/kg ^$\circ$ C.The heat needed to warm 8 kg of water from 20 ^$\circ$ C to 70 ^$\circ$ C is

A)400 kJ.
B)420 kJ.
C)1680 kJ.
D)2016 kJ.

Question 60

In order to double the average energy of the molecules in a gas at 200 K, its temperature must be changed to

A)100 K.
B)400 K.
C)800 K.
D)1600 K.

Question 61

The "heat death" of the universe refers to a possible future in which all of its molecules are

A)at rest.
B)as close together as possible.
C)all moving with the same average speed.
D)all moving in the same direction.

Question 62

If it is to be 40 percent efficient, a heat engine that exhausts heat at 350 K must absorb heat at a minimum temperature of

A)210 K.
B)583 K.
C)875 K.
D)1038 K.

Question 63

A heat engine absorbs heat at 127 ^$\circ$ C and exhausts heat at 77 ^$\circ$ C.Its maximum efficiency is

A)13 percent.
B)39 percent.
C)61 percent.
D)88 percent.

Question 64

Fifty kJ of heat is added to a 10-kg piece of lead at its melting point of 330 ^$\circ$ C and 2 kg of lead melts.The heat of fusion of lead is

A)2.5 kJ/kg.
B)3.3 kJ/kg.
C)5 kJ/kg.
D)25 kJ/kg.

Question 65

The entropy of a body of matter is a measure of

A)how cold it is.
B)how disordered its molecules are.
C)how many of its molecules are at rest.
D)the average kinetic energy of its molecules.

Question 66

An ideal frictionless engine takes in 10 kJ of heat per second when it operates between 500 K and 400 K.The work that the engine does per second is

A)2 kJ.
B)2.5 kJ.
C)8 kJ.
D)10 kJ.