Q: Which of the following is the correct value and units for the universal gas constant $$R$$ when using pressure in atm, volume in L, and temperature in K?

$$0.0821 \text{ L atm} / \text{mol K}$$

Question 1

Which of the following statements best explains why atmospheric pressure is lower at higher elevations?

Accepted Answer

There are fewer air molecules above the surface, resulting in less weight pressing down.

Question 2

A barometer is used to measure atmospheric pressure. If the mercury column in a barometer reads 760 mm, what is the atmospheric pressure in atm?

Accepted Answer

$$1.00 	ext{ atm}$$

Question 3

Which of the following is NOT a standard unit of pressure?

Accepted Answer

Joule (J)

Question 4

A sample of gas at 1.00 atm occupies 2.50 L. If the pressure is increased to 2.00 atm at constant temperature, what is the new volume?

Accepted Answer

$$1.25 	ext{ L}$$

Question 5

Which law describes the direct relationship between the volume of a gas and its temperature (in Kelvin) at constant pressure?

Accepted Answer

Charles's Law

Question 6

A balloon contains 3.00 L of gas at 273 K. If the temperature increases to 546 K at constant pressure, what will be the new volume?

Accepted Answer

$$6.00 	ext{ L}$$

Question 7

According to Avogadro's Law, which of the following statements is true?

Accepted Answer

At constant temperature and pressure, equal volumes of gases contain equal numbers of molecules.

Question 8

A 0.50 mol sample of O$$_2$$ gas occupies 12.1 L at a certain temperature and pressure. What volume would 0.75 mol of O$$_2$$ occupy under the same conditions?

Accepted Answer

$$18.2 	ext{ L}$$

Question 9

Which equation represents the combined gas law?

Accepted Answer

$$\dfrac{P_1$ V_1$}{T_1$} = \dfrac{P_2$ V_2$}{T_2$}$$

Question 10

A sample of gas occupies 5.50 L at 273 K and 1.00 atm. How many moles of gas are present? (Use $$R = 0.0821 	ext{ L atm} / 	ext{mol K})$$

Accepted Answer

$$0.25 	ext{ mol}$$

Question 11

Calculate the volume of 0.85 mol of nitrogen gas at a pressure of 699.2 torr and a temperature of 315 K. ($$R = 0.0821 	ext{ L atm} / 	ext{mol K}$$; $$1 	ext{ atm} = 760 	ext{ torr})$$

Accepted Answer

$$23.8 	ext{ L}$$

Question 12

A sample of methane gas with a volume of 38.0 L at 5°C is heated to 86°C at constant pressure. What is the new volume? (Temperatures must be in Kelvin)

Accepted Answer

$$49.0 	ext{ L}$$

Question 13

A sample of diborane gas (B$$_2H$_6) $$has a pressure of 395 torr at 25°C and a volume of 3.48 L. If the temperature increases to 36°C and the pressure to 468 torr, what will be the new volume?

Accepted Answer

$$3.07 	ext{ L}$$

Question 14

Which of the following is the correct value and units for the universal gas constant $$R$$ when using pressure in atm, volume in L, and temperature in K?

Accepted Answer

$$0.0821 	ext{ L atm} / 	ext{mol K}$$

Question 15

Which of the following scenarios would result in an increase in atmospheric pressure?

Accepted Answer

A cold, dry day at sea level

Question 16

If a gas sample is heated at constant pressure, which of the following will occur according to Charles's Law?

Accepted Answer

The volume of the gas will increase.

Question 17

Which of the following best describes the relationship between pressure and volume for a gas at constant temperature?

Accepted Answer

Pressure and volume are inversely proportional.

Question 18

A gaseous sample contains 0.50 mol Argon at a temperature of 150°C and a pressure of 560 torr. If it is heated to 350°C at constant pressure, what is the change in volume?

Accepted Answer

$$3.0 	ext{ L}$$ increase

Question 19

Which of the following is a real-world application of Boyle's Law?

Accepted Answer

A syringe drawing in liquid as the plunger is pulled back, increasing volume and decreasing pressure.

General Chemistry Study Notes: Gases and Gas Laws

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