400 Exam 4 review

A sample of oxygen gas at a pressure of 1.18 atm occupies a volume of 868 mL. If the gas is compressed at a constant temperature until its pressure is 1.38 atm, the volume of the gas sample will be

• 742 mL

• 102 mL

• 578 mL

• 304 mL

A 9.70-g piece of solid CO₂ (Molar Mass = 44.01 g/mol) is allowed to sublime in a balloon. The final volume of the balloon is 1.00 L at 298 K. What is the pressure of the gas inside the balloon

• 0.186 atm

• 237 atm

• 5.39 atm

• 2.52 atm

A neon gas sample occupies a volume of 3.62 L at 21.6 ^oC . If the pressure remains constant, at what temperature will the volume of the gas be 3.45 L?

• 309 K

• 281 K

• 295 K

• 554 K

A mixture of gases consists of CH₄ at a partial pressure of 143 mm Hg, N₂ at a partial pressure of 469 mm Hg, and O₂ at a partial pressure of 563 mm Hg. Calculate the mole fraction of oxygen in this mixture.

• 0.359

• 0.741

• 0.399

• 0.479

A mixture of krypton and argon gases, in a 8.65-L flask at 22.0 ^oC, contains 15.3 g of krypton and 15.6 g of argon. What is the total pressure in the flask?

• 0.865 atm

• 1.60 atm

• 1.09 atm

• 0.511 atm

The density of a gas is 1.25 g/L at STP. What is its molar mass?

• 22.4 g/mol

• 21.0 g/mol

• 28.0 g/mol

• 17.9 g/mol

The best explanation for the existence of a meniscus observed when water is placed in a glass tube of small diameter is

• the attractive forces between the water molecules and the walls of the container are greater than the attractive forces between the water molecules.

• surface tension of the water causes it to "bead up" inside the container.

• the hydrogen bonds between water molecules are greater than the attractions between the water molecules and the walls of the container.

• the molecules are forced closer together because of London forces.

. For which of the following would permanent dipole-dipole interactions play an important role in determining physical properties in the liquid state?

• BF₃

• ClF

• BeCl₂

• F₂

What intermolecular force(s) of interaction is(are) possible for a molecule of NH₃ shown below?

• London Dispersion

• Dipole - Dipole

• Hydrogen Bonding

• All of these

What is the normal melting point for nitrogen?

• 77.4

• 63.1

• 63.2

• 126.0