Unit 3: Gases

41. The concept of “ideal gas” assumes:

a) No intermolecular forces between gas molecules
b) Strong attractive forces between gas molecules
c) Gas molecules occupy a significant volume
d) Gas molecules move in a fixed pattern
Answer: a) No intermolecular forces between gas molecules

42. The term “partial pressure” is associated with which law?

a) Dalton’s law
b) Boyle’s law
c) Charles’s law
d) Avogadro’s law
Answer: a) Dalton’s law

43. The rate of diffusion of a gas is inversely proportional to:

a) Its molar mass
b) Its temperature
c) Its pressure
d) Its volume
Answer: a) Its molar mass

44. The phenomenon where a gas spreads out to occupy the entire volume of its container is called:

a) Diffusion
b) Effusion
c) Osmosis
d) Condensation
Answer: a) Diffusion

45. The law stating that the pressure of a gas is directly proportional to its temperature when volume is constant is:

a) Boyle’s law
b) Charles’s law
c) Gay-Lussac’s law
d) Avogadro’s law
Answer: c) Gay-Lussac’s law

46. The volume of a gas increases when:

a) Temperature decreases and pressure increases
b) Temperature increases and pressure decreases
c) Temperature decreases and pressure decreases
d) Temperature increases and pressure increases
Answer: b) Temperature increases and pressure decreases

47. In the context of gases, the term “effusion” refers to:

a) The movement of gas through a small hole
b) The escape of gas into a vacuum
c) The diffusion of gas through another gas
d) The dissolution of gas in a liquid
Answer: a) The movement of gas through a small hole

48. The average speed of gas molecules increases with:

a) Decreasing molar mass
b) Increasing pressure
c) Increasing volume
d) Decreasing temperature
Answer: a) Decreasing molar mass

49. The molar volume of an ideal gas is affected by:

a) Temperature and pressure
b) Molar mass and density
c) Volume and mass
d) Pressure and density
Answer: a) Temperature and pressure

50. The Van der Waals equation accounts for real gas behavior by including terms for:

a) Molecular volume and intermolecular forces
b) Temperature and pressure
c) Molar mass and density
d) Volume and number of moles
Answer: a) Molecular volume and intermolecular forces