Question 1

If 150 kcal of thermal energy raises the temperature of 2.0 kg of a material by 400 F°,what is the specific heat capacity of the material?

Accepted Answer

A) 1.35 kcal/kg ∙ C° 
B) 0.75 kcal/kg ∙ C° 
C) 0.34 kcal/kg ∙ C° 
D) 0.19 kcal/kg ∙ C° 
A) 1.35 kcal/kg ∙ C° 
B) 0.75 kcal/kg ∙ C° 
C) 0.34 kcal/kg ∙ C° 
D) 0.19 kcal/kg ∙ C°

Question 2

In an adiabatic compression,200 J of work is done on a gas.What is the change in internal (thermal)energy of the gas during this compression?

Accepted Answer

A) 0 J 
B) 100 J 
C) 200 J 
D) -200 J 
A) 0 J 
B) 100 J 
C) 200 J 
D) -200 J

Question 3

A machine part consists of 0.10 kg of iron (of specific heat 470 J/kg ∙ K )and 0.16 kg of copper (of specific heat 390 J/kg ∙ K).How much thermal energy must be added to the gear to raise its temperature from 18°C to 53°C?

Accepted Answer

A) 910 J 
B) 3800 J 
C) 4000 J 
D) 4400 J 
A) 910 J 
B) 3800 J 
C) 4000 J 
D) 4400 J

Question 4

A gas expands from an initial volume of 30.0 L to a final volume of 65.0 L at a constant pressure of 110 kPa.How much work is done on the gas during this expansion?

Accepted Answer

A) -3.85 kJ 
B) -10.4 kJ 
C) -3850 kJ 
D) -10.4 MJ 
E) -3.85 MJ 
A) -3.85 kJ 
B) -10.4 kJ 
C) -3850 kJ 
D) -10.4 MJ 
E) -3.85 MJ

Question 5

An ideal gas is compressed isothermally to one-third of its initial volume.The resulting pressure will be

Accepted Answer

A) three times as large as the initial value. 
B) less than three times as large as the initial value. 
C) more than three times as large as the initial value. 
D) equal to the initial value. 
E) impossible to predict on the basis of this data. 
A) three times as large as the initial value. 
B) less than three times as large as the initial value. 
C) more than three times as large as the initial value. 
D) equal to the initial value. 
E) impossible to predict on the basis of this data.

Question 6

A lab student drops a 400.0-g piece of metal at 120.0°C into a cup containing 450.0 g of water at 15.0°C.After waiting for a few minutes,the student measures that the final temperature of the system is 40.0°C.What is the specific heat of the metal,assuming that no significant thermal energy is exchanged with the surroundings or the cup? The specific heat of water is 4186 J/kg ∙ K.

Accepted Answer

A) 1470 J/kg ∙ K 
B) 2830 J/kg ∙ K 
C) 3420 J/kg ∙ K 
D) 3780 J/kg ∙ K 
E) 4280 J/kg ∙ K 
A) 1470 J/kg ∙ K 
B) 2830 J/kg ∙ K 
C) 3420 J/kg ∙ K 
D) 3780 J/kg ∙ K 
E) 4280 J/kg ∙ K

Question 7

A concrete wall of a cold storage room measures 3.0 m high,5.0 m wide,and 20 cm thick.The inside wall is to be covered by a layer of wood in order to reduce the rate of thermal energy flow through the wall by 90 percent.The inner surface of the wooden wall is maintained at -10°C and the outer surface of the concrete wall is at 20°C.The thermal conductivities of concrete and wood are 0.80 W/m ∙ K (concrete)and 0.040 W/m ∙ K (wood).What is the temperature difference across the layer of wood?

Accepted Answer

A) 24 C° 
B) 25 C° 
C) 26 C° 
D) 27 C° 
E) 28 C° 
A) 24 C° 
B) 25 C° 
C) 26 C° 
D) 27 C° 
E) 28 C°

Question 8

How much thermal energy is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? The specific heat of lead is 128 J/kg ∙ K.

Accepted Answer

A) 725 J 
B) 576 J 
C) 145 J 
D) 217 J 
E) 288 J 
A) 725 J 
B) 576 J 
C) 145 J 
D) 217 J 
E) 288 J

Question 9

The process shown on the pV diagram in the figure is

Accepted Answer

A) adiabatic. 
B) isothermal. 
C) isochoric. 
D) isobaric. 
A) adiabatic. 
B) isothermal. 
C) isochoric. 
D) isobaric.

Question 10

At room temperature,a typical person transfers energy to the surroundings at the rate of 62 W.If this energy transfer has to be made up by an equivalent food intake,how many kilocalories (food calories)does this person need to consume every day just to make up this energy? (1 cal = 4.186 J)

Accepted Answer

A) 1000 kcal 
B) 1100 kcal 
C) 1300 kcal 
D) 1500 kcal 
E) 1600 kcal 
A) 1000 kcal 
B) 1100 kcal 
C) 1300 kcal 
D) 1500 kcal 
E) 1600 kcal

Question 11

In a flask,114.0 g of water is heated using $67.0 \mathrm {~W}$ of power,with perfect efficiency.How long will it take to raise the temperature of the water from $15 ^ { \circ } \mathrm { C }$ to $25 ^ { \circ } \mathrm { C } \text { ? }$ The specific heat of water is 4186 J/kg ∙ K.

Accepted Answer

A) 71 s 
B) 4.1 s 
C) 17 s 
D) 320,000 s 
A) 71 s 
B) 4.1 s 
C) 17 s 
D) 320,000 s

Question 12

A 400-g block of iron at 400°C is dropped into a calorimeter (of negligible heat capacity)containing 60 g of water at 30°C.How much steam is produced? The latent heat of vaporization of water is 22.6 × 105 J/kg and its specific heat is 4186 J/kg ∙ K.The average specific heat of iron over this temperature range is 560 J/kg ∙ K.

Accepted Answer

A) 22 g 
B) 33 g 
C) 42 g 
D) 54 g 
E) 59 g 
A) 22 g 
B) 33 g 
C) 42 g 
D) 54 g 
E) 59 g

Question 13

How many grams of ice at -17°C must be added to 741 grams of water that is initially at a temperature of $70 ^ { \circ } \mathrm { C }$ to produce water at a final temperature of $ { 12 } ^ { \circ } \mathrm { C } \text {, }$ Assume that no thermal energy is lost to the surroundings and that the container has negligible mass.The specific heat of liquid water is 4190 J/kg ∙ C° and of ice is 2000 J/kg ∙ C°.For water the normal melting point is 0°C and the heat of fusion is 334 × 103 J/kg.The normal boiling point is 100°C and the heat of vaporization is 2.256 × 106 J/kg.

Accepted Answer

Question 14

A glass tea kettle containing 500 g of water is on the stove.The portion of the tea kettle that is in contact with the heating element has an area of 0.090 m2 and is 1.5 mm thick.At a certain moment,the temperature of the water is 75°C,and it is rising at the rate of 3 C° per minute.What is the temperature of the outside surface of the bottom of the tea kettle? Neglect the heat capacity of the kettle,and assume that the inner surface of the kettle is at the same temperature as the water inside.The thermal conductivity of glass is 0.840 W/m ∙ K and the specific heat of water is 4186 J/kg ∙ K.

Accepted Answer

A) 39°C 
B) 92°C 
C) 120°C 
D) 86°C 
E) 77°C 
A) 39°C 
B) 92°C 
C) 120°C 
D) 86°C 
E) 77°C

Question 15

An ideal gas undergoes the process a→b→c→a shown in the pV diagram.In the figure,Pa = Pc = 240 kPa,Vb = Vc = 40 L,Va = 15 L,and Pb = 400 kPa.How much internal (thermal)energy is gained by the gas in this a→b→c→a process?

Accepted Answer

A) 1000 J 
B) 1500 J 
C) 2000 J 
D) 2500 J 
E) 3000 J 
A) 1000 J 
B) 1500 J 
C) 2000 J 
D) 2500 J 
E) 3000 J

Question 16

A person running in place on an exercise machine for 10 min uses up 17 kcal (food calories).Another person exercises by repeatedly lifting two 2.5-kg weights a distance of 50 cm.How many repetitions of this exercise are equivalent to 10 minutes of running in place? Assume that the person uses negligible energy in letting down the weights after each lift.(1 cal = 4.186 J)

Accepted Answer

A) 730 
B) 1450 
C) 1500 
D) 2200 
E) 2900 
A) 730 
B) 1450 
C) 1500 
D) 2200 
E) 2900

Question 17

A 40.0-L container is divided into two equal parts by a rubber membrane.One half of the container has 1.50 moles of an ideal monatomic gas at 250 K,and the other half is a vacuum.The container is well insulated,so there is no exchange of heat with the surroundings.The membrane breaks,and eventually the gas reaches a new equilibrium condition occupying the entire volume.What is the final temperature of the gas?

Accepted Answer

A) 100 K 
B) 125 K 
C) 157 K 
D) 180 K 
E) 250 K 
A) 100 K 
B) 125 K 
C) 157 K 
D) 180 K 
E) 250 K

Question 18

A beaker of negligible heat capacity contains 456 g of ice at -25.0°C.A lab technician begins to supply thermal energy through the process of heating to the container at the rate of 1000 J/min.How long after starting will it take before the temperature starts to rise above 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

Question 19

A 45.0-kg sample of ice is at 0.00° C.How much thermal energy is needed to melt it? For water LF = 334,000 J/kg and LV = 2.256 × 106 J/kg.

Accepted Answer

A) 1.50 × 104 kJ 
B) 4.10 × 106 kJ 
C) 0.00 kJ 
D) 1.02 × 105 kJ 
A) 1.50 × 104 kJ 
B) 4.10 × 106 kJ 
C) 0.00 kJ 
D) 1.02 × 105 kJ

Exam 13: First Law of Thermodynamics

If 150 kcal of thermal energy raises the temperature of 2.0 kg of a material by 400 F°,what is the specific heat capacity of the material?

In an adiabatic compression,200 J of work is done on a gas.What is the change in internal (thermal)energy of the gas during this compression?

A machine part consists of 0.10 kg of iron (of specific heat 470 J/kg ∙ K )and 0.16 kg of copper (of specific heat 390 J/kg ∙ K).How much thermal energy must be added to the gear to raise its temperature from 18°C to 53°C?

A gas expands from an initial volume of 30.0 L to a final volume of 65.0 L at a constant pressure of 110 kPa.How much work is done on the gas during this expansion?

An ideal gas is compressed isothermally to one-third of its initial volume.The resulting pressure will be

How much thermal energy is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? The specific heat of lead is 128 J/kg ∙ K.

The process shown on the pV diagram in the figure is

At room temperature,a typical person transfers energy to the surroundings at the rate of 62 W.If this energy transfer has to be made up by an equivalent food intake,how many kilocalories (food calories)does this person need to consume every day just to make up this energy? (1 cal = 4.186 J)

An ideal gas undergoes the process a→b→c→a shown in the pV diagram.In the figure,Pa = Pc = 240 kPa,Vb = Vc = 40 L,Va = 15 L,and Pb = 400 kPa.How much internal (thermal)energy is gained by the gas in this a→b→c→a process?

A 45.0-kg sample of ice is at 0.00° C.How much thermal energy is needed to melt it? For water LF = 334,000 J/kg and LV = 2.256 × 106 J/kg.

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

Second Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

An ideal gas undergoes the process a→b→c→a shown in the pV diagram.In the figure,P_a = P_c = 240 kPa,V_b = V_c = 40 L,V_a = 15 L,and P_b = 400 kPa.How much internal (thermal)energy is gained by the gas in this a→b→c→a process?

A 45.0-kg sample of ice is at 0.00° C.How much thermal energy is needed to melt it? For water L_F = 334,000 J/kg and L_V = 2.256 × 10⁶ J/kg.