Question 1

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

Accepted Answer

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

Question 2

Molecular motion in a gas is the minimum possible at

Accepted Answer

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

Question 3

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

Accepted Answer

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. 
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 4

A refrigerator

Accepted Answer

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

Question 5

A typical metabolic rate while walking is

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

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

Question 8

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

Accepted Answer

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

Question 9

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

Accepted Answer

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

Question 10

Radiation is emitted

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

Heat transfer by convection occurs

Accepted Answer

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

Question 13

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

Accepted Answer

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. 
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 14

The work output of every heat engine

Accepted Answer

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. 
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 15

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

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

The first law of thermodynamics is the same as the

Accepted Answer

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

Question 18

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

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 19

The heat a refrigerator absorbs from its contents is

Accepted Answer

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. 
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 20

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

Accepted Answer

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. 
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.

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

Molecular motion in a gas is the minimum possible at

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

A refrigerator

A typical metabolic rate while walking is

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

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

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 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

Radiation is emitted

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

Heat transfer by convection occurs

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

The work output of every heat engine

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

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

The first law of thermodynamics is the same as the

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

The heat a refrigerator absorbs from its contents is

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

The Scientific Method

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Energy and the Future

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Exam 5: Matter and Heat

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

Molecular motion in a gas is the minimum possible at

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

A refrigerator

A typical metabolic rate while walking is

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

A temperature of 20 ∘\circ∘ C is the same as

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 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

Radiation is emitted

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

Heat transfer by convection occurs

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

The work output of every heat engine

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

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

The first law of thermodynamics is the same as the

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

The heat a refrigerator absorbs from its contents is

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

The Scientific Method

Motion

Energy

Energy and the Future

Electricity and Magnetism

Waves

The Nucleus

The Atom

The Periodic Law

Crystals, Ions, and Solutions

Chemical Reactions

Organic Chemistry

Atmosphere and Hydrosphere

The Rock Cycle

The Evolving Earth

The Solar System

The Stars

The Universe

Filters

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

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

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

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