Question 1

What is the entropy change when 4 kg of water at 0S1U1P1$\circ$S1S1P0C is frozen into 4 kg of ice at 0S1U1P1$\circ$S1S1P0C?

Accepted Answer

A)  4.9 kJ/K 
B)  an infinite change 
C)  -4.9 kJ/K 
D)  1340 kJ/K 
E)  -33 kJ/K 
A)  4.9 kJ/K 
B)  an infinite change 
C)  -4.9 kJ/K 
D)  1340 kJ/K 
E)  -33 kJ/K

Question 2

What is the maximum possible efficiency of a steam engine operating between a high and low temperature of 550S1U1P1$\circ$S1S1P0C and 180S1U1P1$\circ$S1S1P0C?

Accepted Answer

A)  45% 
B)  67% 
C)  55% 
D)  33% 
E)  82% 
A)  45% 
B)  67% 
C)  55% 
D)  33% 
E)  82%

Question 3

The change in the entropy of the universe due to an operating Carnot engine

Accepted Answer

A)  is zero. 
B)  must be positive. 
C)  must be negative. 
D)  could be positive or negative. 
E)  is meaningless to consider, because a Carnot engine has no connection to entropy. 
A)  is zero. 
B)  must be positive. 
C)  must be negative. 
D)  could be positive or negative. 
E)  is meaningless to consider, because a Carnot engine has no connection to entropy.

Question 4

Three moles of a gas at T = 250 K expand quasi-statically and adiabatically from an initial volume of 30 L to a final volume of 60 L. The change in entropy of the gas during this expansion is (R = 8.314 J/mol·K)

Accepted Answer

A)  17.3 J/K 
B)  18.6 J/K 
C)  -17.4 J/K 
D)  19.5 J/K 
E)  zero 
A)  17.3 J/K 
B)  18.6 J/K 
C)  -17.4 J/K 
D)  19.5 J/K 
E)  zero

Question 5

Of the four steps in the Carnot cycle,

Accepted Answer

A)  two are isothermal and two are isobaric. 
B)  two are adiabatic and two are isobaric. 
C)  two are isovolumic and two are isothermal. 
D)  two are adiabatic and two are isothermal. 
E)  two are adiabatic and two are isovolumic. 
A)  two are isothermal and two are isobaric. 
B)  two are adiabatic and two are isobaric. 
C)  two are isovolumic and two are isothermal. 
D)  two are adiabatic and two are isothermal. 
E)  two are adiabatic and two are isovolumic.

Question 6

A car of mass 2000 kg is traveling at 22.0 m/s on a day when the temperature is 20.0ºC. The driver steps on the brakes and stops the car. By how much does the entropy of the universe increase?

Accepted Answer

A)  1.6 kJ/K 
B)  24 kJ/K 
C)  4.8 $\times$ 105 J/K 
D)  0.15 kJ/K 
E)  3.3 kJ/K 
A)  1.6 kJ/K 
B)  24 kJ/K 
C)  4.8 $\times$ 105 J/K 
D)  0.15 kJ/K 
E)  3.3 kJ/K

Question 7

A heat pump with COP = 5 uses electrical energy W to heat a house. How much heat is pumped into the house?

Accepted Answer

A)  W 
B)  5W 
C)  6W 
D)  4W 
E)  1.2W 
A)  W 
B)  5W 
C)  6W 
D)  4W 
E)  1.2W

Question 8

One mole of an ideal gas undergoes a reversible isothermal expansion from a volume of 1 L to a volume of 2 L. The change in entropy of the gas in terms of the universal gas constant R is

Accepted Answer

A)  R/2 
B)  2R 
C)  R ln(2) 
D)  R ln(½) 
E)  None of these is correct. 
A)  R/2 
B)  2R 
C)  R ln(2) 
D)  R ln(½) 
E)  None of these is correct.

Question 9

The construction of a heat engine operating between temperatures T1 and T2, and having an efficiency greater than that of a Carnot engine operating between the same two temperatures, would constitute a violation of

Accepted Answer

A)  the law of the conservation of energy. 
B)  the first law of thermodynamics. 
C)  the second law of thermodynamics. 
D)  Boyle's law. 
E)  None of these is correct. 
A)  the law of the conservation of energy. 
B)  the first law of thermodynamics. 
C)  the second law of thermodynamics. 
D)  Boyle's law. 
E)  None of these is correct.

Question 10

A container has 0.2 mole of O2 gas and the gas is heated from 0S1U1P1$\circ$S1S1P0C to 100S1U1P1$\circ$S1S1P0C. What is the change in entropy of the gas? (R = 8.314 J/mol·K)

Accepted Answer

A)  1.82 J/K 
B)  1.30 J/K 
C)  0.78 J/K 
D)  26.8 J/K 
E)  zero 
A)  1.82 J/K 
B)  1.30 J/K 
C)  0.78 J/K 
D)  26.8 J/K 
E)  zero

Question 11

A Carnot engine operating between reservoir temperatures of 340º C and 40ºC has an efficiency of

Accepted Answer

A)  37.5% 
B)  49.0% 
C)  60.0% 
D)  62.5% 
E)  88.2% 
A)  37.5% 
B)  49.0% 
C)  60.0% 
D)  62.5% 
E)  88.2%

Question 12

The Carnot efficiency for a heat engine operating between the temperatures of 227º C and 27ºC is

Accepted Answer

A)  20% 
B)  25% 
C)  40% 
D)  88% 
E)  100% 
A)  20% 
B)  25% 
C)  40% 
D)  88% 
E)  100%

Question 13

What is the maximum possible coefficient of performance of a heat pump that is capable of maintaining the interior of a house at 23ºC when the temperature outside is -30ºC?

Accepted Answer

A)  4.59 
B)  3.27 
C)  4.87 
D)  2.63 
E)  5.21 
A)  4.59 
B)  3.27 
C)  4.87 
D)  2.63 
E)  5.21

Question 14

When you make ice cubes, the entropy of the water

Accepted Answer

A)  decreases. 
B)  remains unchanged. 
C)  increases. 
D)  is unchanged as the water cools but decreases as the water freezes. 
E)  decreases while the water is cooling but does not change as it turns to ice. 
A)  decreases. 
B)  remains unchanged. 
C)  increases. 
D)  is unchanged as the water cools but decreases as the water freezes. 
E)  decreases while the water is cooling but does not change as it turns to ice.

Question 15

Entropy is related to probability. An isolated system moves toward

Accepted Answer

A)  a highly ordered state of low probability and high entropy. 
B)  a highly ordered state of high probability and high entropy. 
C)  a state of low order, high probability, and high entropy. 
D)  a state of low order, low probability, and high entropy. 
E)  a state of low order, high probability, and low entropy. 
A)  a highly ordered state of low probability and high entropy. 
B)  a highly ordered state of high probability and high entropy. 
C)  a state of low order, high probability, and high entropy. 
D)  a state of low order, low probability, and high entropy. 
E)  a state of low order, high probability, and low entropy.

Question 16

Use the following diagram to answer the next problem.   
An ideal heat engine uses 0.01 mol of gas and operates between a hot reservoir at TS1U1B1HS1U1B0 = 400 K and cold reservoir at TS1U1B1LS1U1B0 = 300 K, in a cycle from a$\to$b$\to$c$\to$d$\to$a. From a$\to$b the gas undergoes an isothermal expansion, changing its volume from VS1U1B1aS1U1B0 to 2.5VS1U1B1aS1U1B0. From b$\to$c, the pressure is reduced at a constant volume. From c$\to$d, the gas undergoes an isothermal compression, and from d$\to$a, the pressure is increased at a constant volume until the gas is back at the original condition at a.
-How much heat is absorbed in going from a$\to$b?

Accepted Answer

A)  30.5 J 
B)  7.62 J 
C)  22.9 J 
D)  8.31 J 
E)  0.917 J 
A)  30.5 J 
B)  7.62 J 
C)  22.9 J 
D)  8.31 J 
E)  0.917 J

Question 17

If a steam engine operates at half of its theoretical maximum efficiency (emax) and does work at a rate of W J/s, calculate how much heat is discharged per second.

Accepted Answer

A)  W (1 -emax/2) / 2emax  
B)  2W (1 - emax) / emax  
C)  W (1 - emax) / emax  
D)  W (2 - 2emax/2) / (emax/2) 
E)  2W (1 -emax/2) / emax  
A)  W (1 -emax/2) / 2emax  
B)  2W (1 - emax) / emax  
C)  W (1 - emax) / emax  
D)  W (2 - 2emax/2) / (emax/2) 
E)  2W (1 -emax/2) / emax

Question 18

A block of mass m = 0.2 kg slides across a rough horizontal surface with coefficient of kinetic friction $\mu$k = 0.5. What is the change in entropy after the block has moved a distance of 1 m? The temperature of the block and surrounding is 22S1U1P1$\circ$S1S1P0C.

Accepted Answer

A)  4.5$\times$ -2 J/K 
B)  3.3$\times$  -3 J/K 
C)  6.7$\times$10  -3 J/K 
D)  9.0$\times$10  -3 J/K 
E)  zero 
A)  4.5$\times$ -2 J/K 
B)  3.3$\times$  -3 J/K 
C)  6.7$\times$10  -3 J/K 
D)  9.0$\times$10  -3 J/K 
E)  zero

Question 19

A heat pump needs to supply 20 kW of power to maintain the inside temperature of a house at 25S1U1P1$\circ$S1S1P0C while the outside temperature is 0S1U1P1$\circ$S1S1P0C. What is the savings in the electric bill per month by using the heat pump instead of direct electrical heating? Assume that the heat pump/direct heating is on for 4 hours per day and 1 kW.hr costs $0.10.

Accepted Answer

A)  $220 
B)  $20.2 
C)  $200 
D)  $40.4 
E)  $80.8 
A)  $220 
B)  $20.2 
C)  $200 
D)  $40.4 
E)  $80.8

Question 20

A steam engine operates between a high and low temperature of 550S1U1P1$\circ$S1S1P0C and 180S1U1P1$\circ$S1S1P0C. If the steam engine operates at 40% of its theoretical maximum efficiency and does work at a rate of 1000 W, calculate how much heat is discharged per hour.

Accepted Answer

A)  0.8 MJ/hr 
B)  2.8 MJ/hr 
C)  3.4 MJ/hr 
D)  16 MJ/hr 
E)  12 MJ/hr 
A)  0.8 MJ/hr 
B)  2.8 MJ/hr 
C)  3.4 MJ/hr 
D)  16 MJ/hr 
E)  12 MJ/hr

What is the entropy change when 4 kg of water at 0^$\circ$C is frozen into 4 kg of ice at 0^$\circ$C?

What is the maximum possible efficiency of a steam engine operating between a high and low temperature of 550^$\circ$C and 180^$\circ$C?

The change in the entropy of the universe due to an operating Carnot engine

Three moles of a gas at T = 250 K expand quasi-statically and adiabatically from an initial volume of 30 L to a final volume of 60 L. The change in entropy of the gas during this expansion is (R = 8.314 J/mol·K)

Of the four steps in the Carnot cycle,

A car of mass 2000 kg is traveling at 22.0 m/s on a day when the temperature is 20.0ºC. The driver steps on the brakes and stops the car. By how much does the entropy of the universe increase?

A heat pump with COP = 5 uses electrical energy W to heat a house. How much heat is pumped into the house?

One mole of an ideal gas undergoes a reversible isothermal expansion from a volume of 1 L to a volume of 2 L. The change in entropy of the gas in terms of the universal gas constant R is

The construction of a heat engine operating between temperatures T₁ and T₂, and having an efficiency greater than that of a Carnot engine operating between the same two temperatures, would constitute a violation of

A container has 0.2 mole of O₂ gas and the gas is heated from 0^$\circ$C to 100^$\circ$C. What is the change in entropy of the gas? (R = 8.314 J/mol·K)

A Carnot engine operating between reservoir temperatures of 340º C and 40ºC has an efficiency of

The Carnot efficiency for a heat engine operating between the temperatures of 227º C and 27ºC is

What is the maximum possible coefficient of performance of a heat pump that is capable of maintaining the interior of a house at 23ºC when the temperature outside is -30ºC?

When you make ice cubes, the entropy of the water

Entropy is related to probability. An isolated system moves toward

If a steam engine operates at half of its theoretical maximum efficiency (e_max) and does work at a rate of W J/s, calculate how much heat is discharged per second.

A block of mass m = 0.2 kg slides across a rough horizontal surface with coefficient of kinetic friction $\mu$ _k = 0.5. What is the change in entropy after the block has moved a distance of 1 m? The temperature of the block and surrounding is 22^$\circ$C.

A steam engine operates between a high and low temperature of 550^$\circ$C and 180^$\circ$C. If the steam engine operates at 40% of its theoretical maximum efficiency and does work at a rate of 1000 W, calculate how much heat is discharged per hour.

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

Thermal Properties and Processes

Filters

Exam 19: The Second Law of Thermodynamics

What is the entropy change when 4 kg of water at 0 ∘\circ∘ C is frozen into 4 kg of ice at 0 ∘\circ∘ C?

What is the maximum possible efficiency of a steam engine operating between a high and low temperature of 550 ∘\circ∘ C and 180 ∘\circ∘ C?

The change in the entropy of the universe due to an operating Carnot engine

Three moles of a gas at T = 250 K expand quasi-statically and adiabatically from an initial volume of 30 L to a final volume of 60 L. The change in entropy of the gas during this expansion is (R = 8.314 J/mol·K)

Of the four steps in the Carnot cycle,

A car of mass 2000 kg is traveling at 22.0 m/s on a day when the temperature is 20.0ºC. The driver steps on the brakes and stops the car. By how much does the entropy of the universe increase?

A heat pump with COP = 5 uses electrical energy W to heat a house. How much heat is pumped into the house?

One mole of an ideal gas undergoes a reversible isothermal expansion from a volume of 1 L to a volume of 2 L. The change in entropy of the gas in terms of the universal gas constant R is

The construction of a heat engine operating between temperatures T1 and T2, and having an efficiency greater than that of a Carnot engine operating between the same two temperatures, would constitute a violation of

A container has 0.2 mole of O2 gas and the gas is heated from 0 ∘\circ∘ C to 100 ∘\circ∘ C. What is the change in entropy of the gas? (R = 8.314 J/mol·K)

A Carnot engine operating between reservoir temperatures of 340º C and 40ºC has an efficiency of

The Carnot efficiency for a heat engine operating between the temperatures of 227º C and 27ºC is

What is the maximum possible coefficient of performance of a heat pump that is capable of maintaining the interior of a house at 23ºC when the temperature outside is -30ºC?

When you make ice cubes, the entropy of the water

Entropy is related to probability. An isolated system moves toward

If a steam engine operates at half of its theoretical maximum efficiency (emax) and does work at a rate of W J/s, calculate how much heat is discharged per second.

A block of mass m = 0.2 kg slides across a rough horizontal surface with coefficient of kinetic friction μ\muμ k = 0.5. What is the change in entropy after the block has moved a distance of 1 m? The temperature of the block and surrounding is 22 ∘\circ∘ C.

A steam engine operates between a high and low temperature of 550 ∘\circ∘ C and 180 ∘\circ∘ C. If the steam engine operates at 40% of its theoretical maximum efficiency and does work at a rate of 1000 W, calculate how much heat is discharged per hour.

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

Thermal Properties and Processes

Filters

What is the entropy change when 4 kg of water at 0^$\circ$C is frozen into 4 kg of ice at 0^$\circ$C?

What is the maximum possible efficiency of a steam engine operating between a high and low temperature of 550^$\circ$C and 180^$\circ$C?

The construction of a heat engine operating between temperatures T₁ and T₂, and having an efficiency greater than that of a Carnot engine operating between the same two temperatures, would constitute a violation of

A container has 0.2 mole of O₂ gas and the gas is heated from 0^$\circ$C to 100^$\circ$C. What is the change in entropy of the gas? (R = 8.314 J/mol·K)

If a steam engine operates at half of its theoretical maximum efficiency (e_max) and does work at a rate of W J/s, calculate how much heat is discharged per second.

A block of mass m = 0.2 kg slides across a rough horizontal surface with coefficient of kinetic friction $\mu$ _k = 0.5. What is the change in entropy after the block has moved a distance of 1 m? The temperature of the block and surrounding is 22^$\circ$C.

A steam engine operates between a high and low temperature of 550^$\circ$C and 180^$\circ$C. If the steam engine operates at 40% of its theoretical maximum efficiency and does work at a rate of 1000 W, calculate how much heat is discharged per hour.