Question 1

Which of the following equations correctly relates the Celsius and Kelvin temperature scales?

Accepted Answer

$T_K = T_C + 273.15$

Question 2

A steel rod of length $L_0 = 2.0\ \mathrm{m}$ at $20^\circ\mathrm{C}$ is heated to $120^\circ\mathrm{C}$. If the linear expansion coefficient $\alpha$ for steel is $1.2 	imes 10^{-5}\ \mathrm{K}^{-1}$, what is the change in length $\Delta L$?

Accepted Answer

$\Delta L = 0.0024\ \mathrm{m}$

Question 3

Which statement best describes the physical meaning of the root-mean-square speed $v_{rms}$ of an ideal gas?

Accepted Answer

It is the average of the squares of the speeds of all molecules, then square-rooted.

Question 4

Given the ideal gas law $PV = nRT$, which of the following changes will increase the pressure of a fixed amount of gas in a rigid container?

Accepted Answer

Increasing the temperature

Question 5

A $0.5\ \mathrm{kg}$ block of aluminum ($c = 900\ \mathrm{J/kg\cdot K}$) is heated from $25^\circ\mathrm{C}$ to $75^\circ\mathrm{C}$. How much heat $Q$ is required?

Accepted Answer

$Q = 22,500\ \mathrm{J}$

Question 6

Which equation gives the average kinetic energy per particle for an ideal monatomic gas?

Accepted Answer

$K_{avg} = \frac{3}{2}k_B T$

Question 7

A $1.0\ \mathrm{mol}$ sample of an ideal gas at $300\ \mathrm{K}$ is in a $22.4\ \mathrm{L}$ container. What is the pressure $P$ in atmospheres? ($R = 0.0821\ \mathrm{L\cdot atm/(mol\cdot K)}$)

Accepted Answer

$P = 1.00\ \mathrm{atm}$

Question 8

Which of the following best explains why the mean free path of a gas molecule increases as pressure decreases?

Accepted Answer

Lower pressure means fewer molecules per volume, so the average distance between collisions increases.

Question 9

If the volume of a gas is doubled at constant temperature, what happens to the pressure according to Boyle's Law?

Accepted Answer

Pressure halves

Question 10

Which formula correctly expresses the most probable speed $v_{mp}$ of molecules in an ideal gas?

Accepted Answer

$v_{mp} = \sqrt{\frac{2k_B T}{m}}$

Question 11

A $100\ \mathrm{g}$ sample of water at $80^\circ\mathrm{C}$ is mixed with $100\ \mathrm{g}$ of water at $20^\circ\mathrm{C}$ in an insulated container. What is the final equilibrium temperature?

Accepted Answer

$50^\circ\mathrm{C}$

Question 12

Which of the following statements about the phase diagram of water is correct?

Accepted Answer

The triple point is where solid, liquid, and gas phases coexist.

Question 13

Which variable does NOT affect the internal energy of an ideal monatomic gas?

Accepted Answer

Type of gas

Question 14

A $0.2\ \mathrm{kg}$ copper block ($c = 385\ \mathrm{J/kg\cdot K}$) at $100^\circ\mathrm{C}$ is placed in $0.5\ \mathrm{kg}$ of water at $20^\circ\mathrm{C}$ ($c = 4186\ \mathrm{J/kg\cdot K}$). What is the final temperature, assuming no heat loss?

Accepted Answer

$T_f \approx 28^\circ\mathrm{C}$

Question 15

Which of the following is the correct expression for the mean free path $\lambda$ of a gas molecule?

Accepted Answer

$\lambda = \frac{k_B T}{\sqrt{2} \pi d^2 P}$

Question 16

Which of the following best describes the effect of increasing temperature on the distribution of molecular speeds in an ideal gas?

Accepted Answer

The distribution broadens and shifts to higher speeds.

Question 17

Which equation gives the total internal energy $U$ of $N$ particles in an ideal monatomic gas?

Accepted Answer

$U = \frac{3}{2} N k_B T$

Question 18

A $0.3\ \mathrm{kg}$ sample of glass ($c = 840\ \mathrm{J/kg\cdot K}$) cools from $150^\circ\mathrm{C}$ to $50^\circ\mathrm{C}$. How much heat is lost?

Accepted Answer

$Q = 18,900\ \mathrm{J}$

Question 19

Which of the following is NOT an assumption of the kinetic molecular theory for ideal gases?

Accepted Answer

Gas particles exert attractive forces on each other.

Thermal Physics: Temperature, Expansion, Ideal Gases, and Kinetic Theory

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