Unit 8 Practice Test

Which property of an unsaturated solution of sodium chloride in water remains the same when more water is added to the solution?

• density of the solution

• boiling point of the solution

• mass of sodium chloride in the solution

• percent by mass of water in the solution

Under which conditions of temperature and pressure is a gas most soluble in water?

• high temperature and low pressure

• high temperature and high pressure

• low temperature and low pressure

• low temperature and high pressure

A change in pressure would have the greatest effect on the solubility of a

• solid in a liquid

• liquid in a liquid

• gas in a liquid

• liquid in a solid

Compared to distilled water, an aqueous salt solution has

• better electrical conductivity

• poorer electrical conductivity

• a lower boiling point at standard pressure

• a higher freezing point at standard pressure

Which phrase describes the molarity of a solution?

• liters of solute per mole of solution

• liters of solution per mole of solution

• moles of solute per liter of solution

• moles of solution per liter of solution

The concentration of a solution can be expressed in

• milliliters per minute

• parts per million

• grams per kelvin

• joules per gram

Two substances in a mixture differ in density and particle size. These properties can be used to

• separate the substances

• chemically combine the substances

• determine the freezing point of the mixture

• predict the electrical conductivity of the mixture

Answer explanation

The correct choice is to separate the substances based on their differing densities and particle sizes, allowing for physical separation.

A solution consists of 0.50 mole of CaCl₂ dissolved in 100. grams of H₂O at 25°C. Compared to the boiling point and freezing point of 100. grams of H₂O at standard pressure, the solution at standard pressure has

• a lower boiling point and a lower freezing point

• a lower boiling point and a higher freezing point

• a higher boiling point and a lower freezing point

• a higher boiling point and a higher freezing point

Answer explanation

The solution has a lower boiling point due to the presence of a solute, but a higher freezing point because of the colligative properties of the solute.

A mixture consists of sand and an aqueous salt solution. Which procedure can be used to separate the sand, salt, and water from each other?

• Evaporate the water, then filter out the salt.

• Evaporate the water, then filter out the sand.

• Filter out the salt, then evaporate the water.

• Filter out the sand, then evaporate the water.

Answer explanation

Filtering the sand out will leave the water + salt... then the water can be evaporated so the salt is left.

According to Reference Table F, which of these compounds is most soluble at 298 K and 1 atm?

• AgNO₃

• AgCl

• PbCrO₄

• PbCO₃

Answer explanation

AgNO3 is the most soluble compound at 298 K and 1 atm according to Reference Table F.