Question

Question 1

What mass of oxygen gas (O₂) should occupy a 25.0 L container when the pressure is 665 torr and the temperature is 55.0ºC?

		19.3 g
		0.0254 g
		115 g
		617 g
	26.0 g

Question 2

The molar volume of a gas is the volume occupied by one mole of gas.  Calculate the molar volume of an ideal gas when the pressure is 0.250 atm and the temperature is 298 K.

	5.60 L/mol
	22.4 L/mol
	89.6 L/mol
	0.0102 L/mol
	97.8 L/mol

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Question 3

Given that the molar volume of helium (He) gas is 22.4 L/mol under conditions of STP, predict the volume occupied by 0.5 mol neon (Ne) gas at STP?

	2.24 L
	44.8 L
	11.2 L
	56.0 L
	112 L

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Question 4

Calculate the density of argon gas when at a temperature of 255 K and a pressure of 1.5 atm.

	40 g/L
	0.20 g/L
	2.9 g/L
	0.072 g/L
	20 g/L

Question 50.25 pts

Consider two equal-volume balloons under the same conditions of temperature and pressure. One contains helium, and the other contains carbon dioxide.  

Which of the following are the SAME for these two gas samples.  Select all choices that apply.

	Average kinetic energy
	Average particle velocity
	Density
	Mass
	Number of gas particles (atoms or molecules)
	Number of moles of gas

Question 6

Which of the following statements is FALSE?

	In an ideal gas, The combined volume of all the molecules of gas is negligible compared to the total volume in which the gas is contained.
	At a given temperature, the average kinetic energy of H2 gas and O2 gas is the same.
	At a given temperature, O2 gas has a greater average particle velocity than H2.
	At a given temperature, the velocity and kinetic energy of a single gas molecule can vary between collisions.
	In an ideal gas, attractive and repulsive forces forces between gas particles are negligible.

Question 7

Which of the following best describes the relative effusion rates for helium gas and neon gas?

	Helium gas should effuse at a rate 5 times faster than neon.
	Neon gas should effuse at a rate 5 times faster than helium.
	Neon should effuse at a rate 2.2 times faster than helium.
	Helium gas should effuse at a rate 2.2 times faster than neon.
	Helium and neon gases should effuse at the same rate.

Question 80.25 pts

Difluoromethane, CH₂F₂, is a refrigerant that does not cause ozone depletion. Which of the following types of intermolecular forces are present in liquid difluoromethane?

Select all that apply.

	None of these
	Hydrogen bonding
	Dispersion forces
	Dipole-dipole forces

Question 90.25 pts

Which of the following statements best explains the relative boiling points of HBr and Br₂?

	Br2 should have a higher boiling point because  Br2 has stronger dispersion forces than HBr.
	HBr should have a higher boiling point because HBr has dipole-dipole forces and Br2 does not.
	HBr should have a higher boiling point because HBr has hydrogen bonding forces and Br2 does not.
	Br2 should have a higher boiling point because Br2 has dipole-dipole forces and Br2 does not.
	HBr should have a higher boiling point because HBr has stronger dispersion forces than Br2.

Question 10

Which of the following statements best explains the relative boiling points of NH₃ and NF₃?

	NF3 should have a higher boiling point because NF3 has dipole-dipole forces and NH3 does not.
	NF3 should have a higher boiling point because  NF3 has stronger dispersion forces than NH3.
	NH3 should have a higher boiling point because  NH3  has hydrogen bonding and NF3 does not.
	NF3 should have a higher boiling point because NF3 is more polar than NH3.

Answer 1