Question 1

Which of the following is a key assumption of the ideal gas model?

Accepted Answer

Gas particles have negligible volume and only interact during elastic collisions.

Question 2

A sample of helium gas is contained in a rigid, sealed container. If the temperature of the gas is doubled, what happens to the average kinetic energy of the helium atoms?

Accepted Answer

It doubles.

Question 3

Which equation correctly relates the pressure, volume, and temperature of an ideal gas?

Accepted Answer

$$PV = NkT$$

Question 4

A 1.0 mol sample of oxygen gas is at a temperature of $$300\ \mathrm{K}$$ and occupies a volume of $$24.6\ \mathrm{L}. $$What is the pressure of the gas? (Use $$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$1.00\ \mathrm{atm}$$

Question 5

Which of the following best describes the physical meaning of temperature in the kinetic theory of gases?

Accepted Answer

It is a measure of the average translational kinetic energy of the gas particles.

Question 6

If the root-mean-square speed ($$v_{\mathrm{rms}}) of $$nitrogen molecules in air at room temperature is approximately $$500\ \mathrm{m/s}$$, what happens to $$v_{\mathrm{rms}} if $$the temperature is quadrupled?

Accepted Answer

$$v_{\mathrm{rms}}$$ doubles.

Question 7

During which phase change does the latent heat of fusion ($$L_f) $$apply?

Accepted Answer

Solid to liquid

Question 8

A $$50\ \mathrm{g}$$ block of ice at $$0^\circ\mathrm{C} is $$placed in $$100\ \mathrm{g} of $$water at $$20^\circ\mathrm{C}. If $$the latent heat of fusion for ice is $$334\ \mathrm{J/g}$$ and the specific heat of water is $$4.18\ \mathrm{J/g\cdot K}$$, how much heat is required to melt all the ice?

Accepted Answer

$$16,700\ \mathrm{J}$$

Question 9

Which of the following statements about phase changes is correct?

Accepted Answer

During a phase change, all heat added is used to change the phase, not the temperature.

Question 10

A gas in a piston is compressed isothermally. Which of the following is true about the internal energy change ($$\Delta U) of $$the gas?

Accepted Answer

$$\Delta U$$ remains zero.

Question 11

Which equation represents the first law of thermodynamics for a closed system?

Accepted Answer

$$\Delta U = Q - W$$

Question 12

A sample of gas does $$500\ \mathrm{J} of $$work on its surroundings while absorbing $$300\ \mathrm{J} of $$heat. What is the change in internal energy ($$\Delta U) of $$the gas?

Accepted Answer

$$-200\ \mathrm{J}$$

Question 13

Which of the following best describes the work done by a gas during expansion at constant pressure?

Accepted Answer

$$W = P \Delta V$$

Question 14

If a gas undergoes an adiabatic process, which of the following is true?

Accepted Answer

No heat is exchanged with the surroundings ($$Q = 0).$$

Question 15

Which of the following is NOT a characteristic of an ideal gas?

Accepted Answer

Particles can condense into a liquid at low temperatures.

Question 16

A $$2.0\ \mathrm{mol}$$ sample of a monatomic ideal gas is heated at constant volume from $$300\ \mathrm{K} to$$ $$600\ \mathrm{K}. $$What is the change in internal energy? (Use $$U = \frac{3}{2} nRT$$ and $$R = 8.31\ \mathrm{J/mol\cdot K})$$

Accepted Answer

$$24,930\ \mathrm{J}$$

Question 17

Which of the following best explains why the pressure of a gas increases when it is heated at constant volume?

Accepted Answer

The average kinetic energy of the particles increases, causing more frequent and forceful collisions with the walls.

Question 18

Which process describes the direct transition from solid to gas?

Accepted Answer

Sublimation

Question 19

A $$0.5\ \mathrm{mol}$$ sample of an ideal gas at $$400\ \mathrm{K} is $$expanded isothermally from $$5.0\ \mathrm{L} to$$ $$10.0\ \mathrm{L}. $$What is the work done by the gas? (Use $$R = 8.31\ \mathrm{J/mol\cdot K}$$, $$W = nRT \ln\left(\frac{V_f}{V_i}\right))$$

Accepted Answer

$$1,153\ \mathrm{J}$$

Question 20

Which of the following is true about the internal energy of an ideal monatomic gas?

Accepted Answer

It depends only on the temperature.

Lecture 17

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