Q: A piston compresses a gas to half its original volume and three times its original pressure. If the initial temperature was $$0^{\circ}$$\mathrm{C}$$, what is the final temperature?

$$T_f = 1.5 \times 273 \ \mathrm{K} = 409.5 \ \mathrm{K}$$

Q: A constant-volume gas thermometer is placed in contact with a sample. The pressure reads $$65.12 \ \mathrm{kPa}$$, while at the triple point of water it reads $$55.78 \ \mathrm{kPa}. $$What is the temperature of the sample in Kelvin?

$$T = 273.16 \ \mathrm{K} \times \dfrac{65.12}{55.78} = 318.8 \ \mathrm{K}$$

Question 1

Which of the following best describes the molecular arrangement in a solid?

Accepted Answer

Atoms vibrate around equilibrium positions but otherwise have fixed positions.

Question 2

A cylindrical lead pipe has an outer diameter of 4.0 cm, an inner diameter of 3.5 cm, and a length of 50 cm. Given the mass density of lead is $$p = 11,300 \ \mathrm{kg/m^3$}$$, what is the mass of the pipe?

Accepted Answer

$$M = 1.7 \ \mathrm{kg}$$

Question 3

Which statement about the number of molecules in a mole of hydrogen gas versus a mole of oxygen gas is correct?

Accepted Answer

They each contain the same number of molecules.

Question 4

Which temperature change represents the largest increase?

Accepted Answer

Both $$1^{\circ}$$\mathrm{C}$$ and 1$$ \ \mathrm{K}$$, which are the same and larger than 1$$^{\circ}$$\mathrm{F}$$

Question 5

A steel pipe of length $$L = 55 \ \mathrm{m} is $$heated from $$T = 5$$^{\circ}$$\mathrm{C} to$$ $$T = 155$$^{\circ}$$\mathrm{C}. $$Given the coefficient of linear expansion for steel is $$\alpha = 1.1 	imes 10$$^{-5}$$ \ \mathrm{C}^{-1}$$, what is the change in length $$\Delta L$$?

Accepted Answer

$$\Delta L = 0.091 \ \mathrm{m}$$

Question 6

If a metal plate has a circular hole and the plate is heated, what happens to the diameter of the hole?

Accepted Answer

It increases.

Question 7

Which of the following best explains why water boils at a lower temperature at high altitudes?

Accepted Answer

The atmospheric pressure is lower, so the liquid-gas boundary occurs at a lower temperature.

Question 8

Which equation represents the ideal-gas law in terms of the number of molecules $$N$$?

Accepted Answer

$$pV = Nk_B T$$

Question 9

A sealed, rigid container of gas is heated from $$100^{\circ}$$\mathrm{C}$$ to 200$$^{\circ}$$\mathrm{C}. By $$what factor does the pressure change?

Accepted Answer

1.13

Question 10

A piston compresses a gas to half its original volume and three times its original pressure. If the initial temperature was $$0^{\circ}$$\mathrm{C}$$, what is the final temperature?

Accepted Answer

$$T_f = 1.5 	imes 273 \ \mathrm{K} = 409.5 \ \mathrm{K}$$

Question 11

Which process is represented by a constant-volume change in a gas?

Accepted Answer

Isochoric process

Question 12

A cylinder of gas has a frictionless, tightly sealed piston of mass $$M. $$The gas temperature is increased from $$27^{\circ}$$\mathrm{C}$$ to 127$$^{\circ}$$\mathrm{C} at $$constant pressure. What is the final-to-initial volume ratio $$V_f/V_i$$?

Accepted Answer

1.50

Question 13

Which of the following is true for an isothermal process involving an ideal gas?

Accepted Answer

$$pV = 	ext{constant}$$

Question 14

A gas undergoes a two-step process: first, it is expanded isothermally until its volume doubles; then, it is compressed isobarically until it returns to its original volume. If the initial pressure is $$2.0 \ \mathrm{atm}$$ and the initial temperature is $$200^{\circ}$$\mathrm{C}$$, what is the final temperature in $$^{\circ}\mathrm{C}$$?

Accepted Answer

$$473^{\circ}$$\mathrm{C}$$

Question 15

Which of the following statements about the ideal-gas model is correct?

Accepted Answer

It assumes atoms interact only through perfectly elastic collisions.

Question 16

If the pressure of liquid water is suddenly decreased at room temperature, what phase change is most likely to occur?

Accepted Answer

Boil

Question 17

Which of the following is the correct expression for the number of moles $$n in a $$sample of mass $$M$$ and molar mass $$M_m$$?

Accepted Answer

$$n = \dfrac{M}{M_m}$$

Question 18

A constant-volume gas thermometer is placed in contact with a sample. The pressure reads $$65.12 \ \mathrm{kPa}$$, while at the triple point of water it reads $$55.78 \ \mathrm{kPa}. $$What is the temperature of the sample in Kelvin?

Accepted Answer

$$T = 273.16 \ \mathrm{K} 	imes \dfrac{65.12}{55.78} = 318.8 \ \mathrm{K}$$

Question 19

Which of the following best describes the triple point of water?

Accepted Answer

The temperature and pressure where solid, liquid, and gas phases of water coexist in equilibrium.

Chapter 18: A Macroscopic Description of Matter – Study Notes

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