Question 1

Which of the following statements best explains why gases exert pressure on the walls of their container?

Accepted Answer

Gas molecules collide with the walls, transferring momentum.

Question 2

A barometer is used to measure atmospheric pressure. If the atmospheric pressure decreases, what happens to the height of the mercury column in a barometer?

Accepted Answer

The height of the mercury column decreases.

Question 3

Which of the following is the correct mathematical expression for Boyle's Law?

Accepted Answer

$$P_1V_1 = P_2V_2$$

Question 4

According to Charles's Law, what happens to the volume of a gas as the temperature increases at constant pressure?

Accepted Answer

The volume increases.

Question 5

Which of the following gases would deviate most from ideal behavior under high pressure and low temperature?

Accepted Answer

Carbon dioxide ($$CO_2)$$

Question 6

A rigid flask contains 1 mole of methane ($$CH_4) at$$ $$0^	ext{o}C in a$$ $$250.0 mL $$container. The experimental pressure is $$74.3$$ atm. What is the predicted pressure using the ideal gas law?

Accepted Answer

$$73.2$$ atm

Question 7

Which of the following is the correct form of the van der Waals equation for real gases?

Accepted Answer

$$\left(P + \frac{a n^2$}{V^2$}\right)(V - nb) = nRT$$

Question 8

If you double the temperature and halve the pressure of a gas sample, what happens to the volume, assuming the amount of gas is constant?

Accepted Answer

The volume quadruples.

Question 9

Which of the following best describes Avogadro's Law?

Accepted Answer

At constant temperature and pressure, the volume of a gas is directly proportional to the number of moles.

Question 10

A mixture contains $$2$$ mol $$CO_2$$, $$1$$ mol $$O_2$$, and $$3$$ mol $$NH_3 in a$$ $$10 L $$container at $$300 K. If $$the total pressure is $$5$$ atm, what is the partial pressure of $$NH_3$$?

Accepted Answer

$$1.67$$ atm

Question 11

Which of the following conditions would make a gas behave most ideally?

Accepted Answer

Low pressure and high temperature

Question 12

What is the density (in $$g/L) of$$ $$O_2$$ gas at $$2.0$$ atm and $$25^	ext{o}C$$? ($$M_{O_2$} = 32.00 g/$$mol, $$R = 0.0821 L$$·atm/mol·K)

Accepted Answer

$$2.62 g/L$$

Question 13

Which of the following is the correct expression for the mole fraction ($$X_A) of $$component A in a mixture?

Accepted Answer

$$X_A = \frac{n_A}{n_{total}}$$

Question 14

Calculate the root mean square speed ($$u_{rms}) of$$ $$N_2$$ molecules at room temperature ($$T = 298 K$$). ($$M_{N_2$} = 28.0 g/$$mol, $$R = 8.314 J/$$mol·K)

Accepted Answer

$$u_{rms} = 517 m/s$$

Question 15

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

Accepted Answer

Gas molecules have attractive forces between them.

Question 16

A student isolates an unknown gas with a density of $$2.617 g/L at $$room temperature ($$25^	ext{o}C) $$and $$2.0$$ atm. What is the molar mass of the gas?

Accepted Answer

$$32.2 g/$$mol

Question 17

Which of the following best explains why $$CO_2$$ and $$NH_3$$ have true molar volumes that differ significantly from the ideal value of $$22.4 L/$$mol?

Accepted Answer

They have strong intermolecular forces and/or significant molecular volume.

Question 18

In a chemical reaction, $$4$$ mol $$C_4H_6N_4O_8 ($$solid) decomposes to produce $$12$$ mol $$CO_2 ($$gas), $$6$$ mol $$N_2 ($$gas), $$O_2 ($$gas), and $$10$$ mol $$H_2O ($$gas). Why might this reaction be considered explosive?

Accepted Answer

It produces a large increase in the number of gas molecules.

Question 19

Which of the following best describes the effect of increasing the value of 'b' in the van der Waals equation?

Accepted Answer

It accounts for the volume occupied by gas molecules, reducing the usable volume.

General Chemistry Study Notes: Properties and Laws of Gases

Guida di studio - Domande di pratica

Study guide - Flashcard