Q: How much heat is required to raise the temperature of a 0.500 kg aluminum pan ($$c_{\mathrm{Al}} = 900 \ \mathrm{J}/\mathrm{kg} \cdot \mathrm{K}) $$and 0.250 kg of water ($$c_{\mathrm{water}} = 4186 \ \mathrm{J}/\mathrm{kg} \cdot \mathrm{K}) $$from 20 ºC to 80 ºC?

$$Q = 0.5 \times 900 \times 60 + 0.25 \times 4186 \times 60 = 27,000 + 62,790 = 89,790 \ \mathrm{J}$$

Q: Calculate the number of molecules in 1 m³ of an ideal gas at standard temperature and pressure (STP: 0ºC, 1 atm). ($$k = 1.38 \times 10$$^{-23}$$ \ \mathrm{J/K}$$, $$P = 1.01 \times 10^5$ \ \mathrm{N/m}^2$$, $$T = 273 \ \mathrm{K})$$

$$2.68 \times 10$$^{25}$$ molecules

Question 1

Which of the following best describes the mechanical equivalent of heat?

Accepted Answer

The conversion between mechanical work and heat, where $$1 \ \mathrm{cal} = 4.186 \ \mathrm{J}.$$

Question 2

A farmer lifts a 23.5 kg bale of hay to a height of 1.1 m. If a 485 Calorie milkshake is consumed, how many bales can the farmer lift? (Assume $$1 \ \mathrm{Calorie} = 4186 \ \mathrm{J})$$

Accepted Answer

About 90.5 bales

Question 3

Which equation correctly defines heat capacity?

Accepted Answer

$$C = \frac{Q}{\Delta T}$$

Question 4

If 493 J of heat is added to 1 kg of iron with a heat capacity of 488 J/K, what is the temperature change?

Accepted Answer

$$\Delta T = 1.01 \ \mathrm{K}$$

Question 5

Which of the following statements about specific heat is correct?

Accepted Answer

Specific heat is the amount of heat required to raise the temperature of 1 kg of a substance by 1 K.

Question 6

Two blocks, one of aluminum and one of lead, have equal volumes and are heated to the same temperature. Which will melt more wax when placed on a wax block?

Accepted Answer

The lead block, because it has a higher density and lower specific heat.

Question 7

How much heat is required to raise the temperature of a 0.500 kg aluminum pan ($$c_{\mathrm{Al}} = 900 \ \mathrm{J}/\mathrm{kg} \cdot \mathrm{K}) $$and 0.250 kg of water ($$c_{\mathrm{water}} = 4186 \ \mathrm{J}/\mathrm{kg} \cdot \mathrm{K}) $$from 20 ºC to 80 ºC?

Accepted Answer

$$Q = 0.5 	imes 900 	imes 60 + 0.25 	imes 4186 	imes 60 = 27,000 + 62,790 = 89,790 \ \mathrm{J}$$

Question 8

In a calorimetry experiment, 54 g of water at 35 ºC is poured into a 65 g aluminum cup at 11 ºC. What is the final temperature, assuming no heat is lost to the surroundings? ($$c_{\mathrm{water}} = 4186 \ \mathrm{J}/\mathrm{kg} \cdot \mathrm{K}$$, $$c_{\mathrm{Al}} = 900 \ \mathrm{J}/\mathrm{kg} \cdot \mathrm{K})$$

Accepted Answer

About 27 ºC

Question 9

Which method of heat transfer does NOT require a medium (material) to transfer energy?

Accepted Answer

Radiation

Question 10

Which of the following is the correct form of the ideal gas law in terms of molecules?

Accepted Answer

$$PV = NkT$$

Question 11

A sealed room is heated, raising the air temperature but keeping the volume constant. What happens to the air pressure?

Accepted Answer

It increases.

Question 12

Calculate the number of molecules in 1 m³ of an ideal gas at standard temperature and pressure (STP: 0ºC, 1 atm). ($$k = 1.38 	imes 10$$^{-23}$$ \ \mathrm{J/K}$$, $$P = 1.01 	imes 10^5$ \ \mathrm{N/m}^2$$, $$T = 273 \ \mathrm{K})$$

Accepted Answer

$$2.68 	imes 10$$^{25}$$ molecules

Question 13

Which law states that the volume of a gas is directly proportional to its temperature at constant pressure?

Accepted Answer

Charles’s Law

Question 14

What is the value of the universal gas constant $$R in SI $$units?

Accepted Answer

$$R = 8.31 \ \mathrm{J}/\mathrm{mol} \cdot \mathrm{K}$$

Question 15

If you increase the temperature of a liquid, what happens to the number of high-speed molecules that escape into the gas phase?

Accepted Answer

It increases.

Question 16

Which of the following best describes phase equilibrium?

Accepted Answer

A state where the rate of molecules leaving and entering a phase is equal.

Question 17

Which method of heat transfer is primarily responsible for ocean currents?

Accepted Answer

Convection

Question 18

A bike tire has a volume of $$2.00 	imes 10$$^{-3}$$ \ \mathrm{m}^3$$, a pressure of $$7.00 	imes 10^5$ \ \mathrm{N/m}^2$$, and a temperature of 18 ºC. How many moles of gas are in the tire? ($$R = 8.31 \ \mathrm{J}/\mathrm{mol} \cdot \mathrm{K})$$

Accepted Answer

$$n = 0.56$$ moles

Question 19

Which of the following is NOT a correct statement about the kinetic theory of gases?

Accepted Answer

The average kinetic energy of a gas is independent of temperature.

Phases, Phase Changes, and Thermal Properties of Matter

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