Q: If an ideal gas absorbs $$5.00 \times 10^3$\ \mathrm{J} of $$energy and does $$2.00 \times 10^3$\ \mathrm{J} of $$work on the environment, what is the change in internal energy $$\Delta U$$?

$$\Delta U = 3.00 \times 10^3$\ \mathrm{J}$$

Q: A heat engine receives $$3.50 \times 10^3$\ \mathrm{J}$$ from a boiler at $$500\ \mathrm{K}$$ and expels energy to a cold reservoir at $$300\ \mathrm{K}. $$How much energy is transferred to the cold reservoir?

$$2.10 \times 10^3$\ \mathrm{J}$$

Question 1

Which law of thermodynamics states that if two objects are each in thermal equilibrium with a third object, then they are in thermal equilibrium with each other?

Accepted Answer

The Zeroth Law of Thermodynamics

Question 2

A constant-volume gas thermometer is used to measure temperature. If the pressure of the gas is zero at $$-273.15\ ^\circ \mathrm{C}$$, what is this temperature called?

Accepted Answer

Absolute zero

Question 3

Convert a temperature of $$68\ ^\circ \mathrm{F} to $$Celsius using the formula $$T_C = \frac{5}{9}(T_F - 32). $$What is the result?

Accepted Answer

$$20\ ^\circ \mathrm{C}$$

Question 4

Which physical property is NOT commonly used in thermometers to measure temperature?

Accepted Answer

The mass of a gas

Question 5

A heat engine absorbs $$Q_h$$ from a hot reservoir and expels $$Q_c to a $$cold reservoir. What is the formula for its thermal efficiency $$e$$?

Accepted Answer

$$e = 1 - \frac{Q_c}{Q_h}$$

Question 6

If an ideal gas absorbs $$5.00 	imes 10^3$\ \mathrm{J} of $$energy and does $$2.00 	imes 10^3$\ \mathrm{J} of $$work on the environment, what is the change in internal energy $$\Delta U$$?

Accepted Answer

$$\Delta U = 3.00 	imes 10^3$\ \mathrm{J}$$

Question 7

What is the SI unit for entropy?

Accepted Answer

Joule per Kelvin ($$\mathrm{J}/\mathrm{K})$$

Question 8

A Carnot engine operates between a hot reservoir at $$500\ \mathrm{K}$$ and a cold reservoir at $$300\ \mathrm{K}. $$What is its maximum possible efficiency?

Accepted Answer

$$e = 0.60$$

Question 9

Which statement best describes the Second Law of Thermodynamics?

Accepted Answer

No heat engine can convert all absorbed energy into work.

Question 10

What is the change in entropy $$\Delta S$$ when $$7.35 	imes 10^3$\ \mathrm{J} of $$energy is absorbed at $$600\ \mathrm{K}$$?

Accepted Answer

$$\Delta S = 12.3\ \mathrm{J}/\mathrm{K}$$

Question 11

Which process is characterized by no heat exchange with the surroundings?

Accepted Answer

Adiabatic process

Question 12

A refrigerator extracts $$Q_c$$ from the cold reservoir and requires work $$W. $$What is the coefficient of performance (COP) for cooling mode?

Accepted Answer

$$COP = \frac{Q_c}{W}$$

Question 13

Which scientist is credited with the statistical explanation of the Second Law of Thermodynamics?

Accepted Answer

Boltzmann

Question 14

What is the internal energy $$U of a $$monoatomic ideal gas, given by $$n$$ moles at temperature $$T$$?

Accepted Answer

$$U = \frac{3}{2}nRT$$

Question 15

Which of the following is NOT a consequence of the Second Law of Thermodynamics?

Accepted Answer

The internal energy of a system always increases

Question 16

A heat engine receives $$3.50 	imes 10^3$\ \mathrm{J}$$ from a boiler at $$500\ \mathrm{K}$$ and expels energy to a cold reservoir at $$300\ \mathrm{K}. $$How much energy is transferred to the cold reservoir?

Accepted Answer

$$2.10 	imes 10^3$\ \mathrm{J}$$

Question 17

Which statement about entropy is correct?

Accepted Answer

Entropy is a function of the state of the system.

Question 18

What is the main reason real engines are less efficient than Carnot engines?

Accepted Answer

They are irreversible due to friction and rapid cycles.

Question 19

Which temperature scale is defined by the triple point of water and absolute zero?

Accepted Answer

Kelvin scale

Question 20

A person consumes 1 liter of oxygen, releasing 20 kJ of energy. If their oxygen consumption rate is $$\Delta V_{O_2$}/\Delta t = 2\ \mathrm{L/s}$$, what is their metabolic rate $$\Delta U/\Delta t$$?

Accepted Answer

$$40\ \mathrm{kJ/s}$$

Chapter 11: Using Energy – Thermodynamics and Energy Transformations

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