Question 1

Your lungs hold 4.2 L of air at a temperature of 27°C and a pressure of 101.3 kPa. How many moles of air do your lungs hold?

Accepted Answer

A)  0.15 moles 
B)  0.17 moles 
C)  0.19 moles 
D)  0.21 moles 
E)  0.23 moles 
A)  0.15 moles 
B)  0.17 moles 
C)  0.19 moles 
D)  0.21 moles 
E)  0.23 moles

Question 2

Phase equilibrium between the gaseous and liquid states describes the situation when

Accepted Answer

A)  no more molecules leave the liquid and enter the gas. 
B)  no more molecules leave the gas and enter the liquid. 
C)  as many molecules go from liquid to gas as from gas to liquid. 
D)  the liquid is boiling. 
E)  None of the other choices is correct. 
A)  no more molecules leave the liquid and enter the gas. 
B)  no more molecules leave the gas and enter the liquid. 
C)  as many molecules go from liquid to gas as from gas to liquid. 
D)  the liquid is boiling. 
E)  None of the other choices is correct.

Question 3

The internal energy of an ideal gas does not depend on the pressure.

Accepted Answer

A) True 
 B)False

Question 4

How many molecules are in:
(a) 1.0 cm3 of AIR at STP?
(b) 1.0 cm3 of HELIUM at STP?

Accepted Answer

2.7 × 10¹⁹ m

Question 5

How much heat is required to change 456 g of ice at -25.0°C into water at 25.0°C? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33.5 × 104 J/kg.

Accepted Answer

A)  224 kJ 
B)  153 kJ 
C)  112 kJ 
D)  71.5 kJ 
E)  72.5 kJ 
A)  224 kJ 
B)  153 kJ 
C)  112 kJ 
D)  71.5 kJ 
E)  72.5 kJ

Question 6

The molecular weight of nitrogen is 28 g/mol. What is the rms speed of nitrogen molecules at 8.0°C?

Accepted Answer

A)  450 m/s 
B)  500 m/s 
C)  550 m/s 
D)  600 m/s 
E)  650 m/s 
A)  450 m/s 
B)  500 m/s 
C)  550 m/s 
D)  600 m/s 
E)  650 m/s

Question 7

In tropical areas of the world where refrigeration is not readily available, people store water in unglazed clay pots. This makes the water stay at a cool temperature, much cooler than the ambient temperature. How is that possible?

Accepted Answer

A small amount of water works

Question 8

In an experiment to measure the thermal conductivity of a certain material, a slab of material 10.0 mm thick separates a steam chamber from a block of ice with a square cross-section of 8.00 cm × 8.00 cm. In 5.00 minutes of running the experiment, 64.0 g of ice have melted. What is the coefficient of thermal conductivity of this material? The latent heat of fusion of water is 33.5 × 104 J/kg.

Accepted Answer

A)  0.130 W/m/K 
B)  0.250 W/m/K 
C)  0.440 W/m/K 
D)  0.620 W/m/K 
E)  1.10 W/m/K 
A)  0.130 W/m/K 
B)  0.250 W/m/K 
C)  0.440 W/m/K 
D)  0.620 W/m/K 
E)  1.10 W/m/K

Question 9

A steel bar with a cross-sectional area of 1.00 × 10-4 m2 is heated to 100°C and then it is clamped at both ends with clamps that are 2.0 m apart. When the bar cools to 20°C what is the force exerted by the bar on the clamps? The coefficient of thermal expansion of steel is
12 × 10-6 K-1 and Young's modulus for steel is 20 × 1010 N/m2.

Accepted Answer

A)  1.9 × 104 N 
B)  3.8 × 104 N 
C)  1.9 × 103 N 
D)  3.8 × 103 N 
E)  1.9 × 105 N 
A)  1.9 × 104 N 
B)  3.8 × 104 N 
C)  1.9 × 103 N 
D)  3.8 × 103 N 
E)  1.9 × 105 N

Question 10

Lead has a latent heat of fusion of 2.32 × 104 J/kg, and a specific heat of 128 J/(kg K), and a melting point of 228°C. The ambient temperature is 16°C. A 30-g lead bullet hits a solid surface and comes to a complete stop. What would the velocity of the bullet have to be in order for it to melt completely when it hits the wall, assuming that all its kinetic energy is transformed into heat?

Accepted Answer

A)  207 m/s 
B)  215 m/s 
C)  232 m/s 
D)  273 m/s 
E)  318 m/s 
A)  207 m/s 
B)  215 m/s 
C)  232 m/s 
D)  273 m/s 
E)  318 m/s

Question 11

The vapor pressure of water at 20°C is 2330 Pa. Suppose that you build a barometer that uses water as its working fluid instead of mercury. What would the height of the column of water be when the external pressure is 101 kPa and the water temperature is 20°C?

Accepted Answer

A)  10.1 m 
B)  10.3 m 
C)  10.5 m 
D)  10.7 m 
E)  10.9 m 
A)  10.1 m 
B)  10.3 m 
C)  10.5 m 
D)  10.7 m 
E)  10.9 m

Question 12

A 35-g block of ice at -14°C is dropped into a calorimeter (of negligible heat capacity) containing 400 g of water at 0°C. When the system reaches equilibrium, how much ice is left in the calorimeter? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33.5 × 104 J/kg.

Accepted Answer

A)  32 g 
B)  33 g 
C)  35 g 
D)  38 g 
E)  41 g 
A)  32 g 
B)  33 g 
C)  35 g 
D)  38 g 
E)  41 g

Question 13

A balloon containing 2.0 m3 of hydrogen gas rises from a location at which the temperature is 22°C and the pressure is 101 kPa to a location where the temperature is -39°C and the pressure is 20 kPa. If the balloon is free to expand so that the pressure of the gas inside is equal to the ambient pressure, what is the new volume of the balloon?

Accepted Answer

A)  4.0 m3 
B)  6.0 m3 
C)  8.0 m3 
D)  10 m3 
E)  12 m3 
A)  4.0 m3 
B)  6.0 m3 
C)  8.0 m3 
D)  10 m3 
E)  12 m3

Question 14

A 44-g block of ice at -15°C is dropped into a calorimeter (of negligible heat capacity) containing 100 g of water at 5°C. When equilibrium is reached, how much of the ice will have melted? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is
33)5 × 104 J/kg.

Accepted Answer

A)  2.1 g 
B)  21 g 
C)  5.2 g 
D)  52 g 
E)  4.4 g 
A)  2.1 g 
B)  21 g 
C)  5.2 g 
D)  52 g 
E)  4.4 g

Question 15

A runner generates 1260 W of thermal energy. If this heat has to be removed by evaporation, how much water does this runner lose in 15 minutes of running? The latent heat of vaporization of water is 22.6 × 105 J/kg.

Accepted Answer

A)  50 g 
B)  500 g 
C)  35 g 
D)  350 g 
E)  40 g 
A)  50 g 
B)  500 g 
C)  35 g 
D)  350 g 
E)  40 g

Question 16

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

Accepted Answer

A)  heat of fusion. 
B)  heat of vaporization. 
C)  heat of melting. 
D)  heat of freezing. 
E)  heat of condensation. 
A)  heat of fusion. 
B)  heat of vaporization. 
C)  heat of melting. 
D)  heat of freezing. 
E)  heat of condensation.

Question 17

When we say that a material sample has reached its elastic limit, we mean that

Accepted Answer

A)  if any further stress is applied, the sample will break. 
B)  if any further stress is applied, the deformation of the sample will not be reversible. 
C)  the deformation no longer follows Hooke's law. 
D)  the material will continue deforming with no further additional stress. 
E)  None of the other choices is correct. 
A)  if any further stress is applied, the sample will break. 
B)  if any further stress is applied, the deformation of the sample will not be reversible. 
C)  the deformation no longer follows Hooke's law. 
D)  the material will continue deforming with no further additional stress. 
E)  None of the other choices is correct.

Question 18

When a solid melts

Accepted Answer

A)  the temperature of the substance increases. 
B)  the temperature of the substance decreases. 
C)  heat energy leaves the substance. 
D)  heat energy enters the substance. 
A)  the temperature of the substance increases. 
B)  the temperature of the substance decreases. 
C)  heat energy leaves the substance. 
D)  heat energy enters the substance.

Question 19

Two moles of gas are at STP. If the temperature changes to 47.° C and the pressure decreases to half of what it was, what volume do the two moles now occupy?

Accepted Answer

The answer of Two moles of gas are at STP....

Question 20

Which of the following best explains why sweating is important to humans in maintaining suitable body temperature?

Accepted Answer

A)  Functioning of the sweat gland absorbs energy that otherwise would go into heating the body. 
B)  The high specific heat of water on the skin absorbs heat from the body. 
C)  Evaporation of moisture from the skin extracts heat from the body. 
D)  Moisture on the skin increases thermal conductivity, thereby allowing heat to flow out of the body more effectively. 
E)  None of the other choices is correct. 
A)  Functioning of the sweat gland absorbs energy that otherwise would go into heating the body. 
B)  The high specific heat of water on the skin absorbs heat from the body. 
C)  Evaporation of moisture from the skin extracts heat from the body. 
D)  Moisture on the skin increases thermal conductivity, thereby allowing heat to flow out of the body more effectively. 
E)  None of the other choices is correct.

Exam 17: Phases and Phase Changes

Your lungs hold 4.2 L of air at a temperature of 27°C and a pressure of 101.3 kPa. How many moles of air do your lungs hold?

Phase equilibrium between the gaseous and liquid states describes the situation when

The internal energy of an ideal gas does not depend on the pressure.

How many molecules are in: (a) 1.0 cm3 of AIR at STP? (b) 1.0 cm3 of HELIUM at STP?

How much heat is required to change 456 g of ice at -25.0°C into water at 25.0°C? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33.5 × 104 J/kg.

The molecular weight of nitrogen is 28 g/mol. What is the rms speed of nitrogen molecules at 8.0°C?

In tropical areas of the world where refrigeration is not readily available, people store water in unglazed clay pots. This makes the water stay at a cool temperature, much cooler than the ambient temperature. How is that possible?

The vapor pressure of water at 20°C is 2330 Pa. Suppose that you build a barometer that uses water as its working fluid instead of mercury. What would the height of the column of water be when the external pressure is 101 kPa and the water temperature is 20°C?

A 44-g block of ice at -15°C is dropped into a calorimeter (of negligible heat capacity) containing 100 g of water at 5°C. When equilibrium is reached, how much of the ice will have melted? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33)5 × 104 J/kg.

A runner generates 1260 W of thermal energy. If this heat has to be removed by evaporation, how much water does this runner lose in 15 minutes of running? The latent heat of vaporization of water is 22.6 × 105 J/kg.

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

When we say that a material sample has reached its elastic limit, we mean that

When a solid melts

Two moles of gas are at STP. If the temperature changes to 47.° C and the pressure decreases to half of what it was, what volume do the two moles now occupy?

Which of the following best explains why sweating is important to humans in maintaining suitable body temperature?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric Potential Energy

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

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How many molecules are in: (a) 1.0 cm³ of AIR at STP? (b) 1.0 cm³ of HELIUM at STP?

How much heat is required to change 456 g of ice at -25.0°C into water at 25.0°C? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33.5 × 10⁴ J/kg.

A 44-g block of ice at -15°C is dropped into a calorimeter (of negligible heat capacity) containing 100 g of water at 5°C. When equilibrium is reached, how much of the ice will have melted? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is 33)5 × 10⁴ J/kg.

A runner generates 1260 W of thermal energy. If this heat has to be removed by evaporation, how much water does this runner lose in 15 minutes of running? The latent heat of vaporization of water is 22.6 × 10⁵ J/kg.