Q: A wine is labeled as '11.5% alcohol by volume.' How many milliliters of alcohol are present in a 750 mL bottle?

$$\frac{11.5}{100} \times 750 = 86.25 mL$$

Question 1

Which of the following statements best describes a mixture?

Accepted Answer

A mixture consists of two or more substances physically mixed, with variable composition and properties that can be separated by physical means.

Question 2

Which separation technique would be most appropriate for isolating salt from seawater?

Accepted Answer

Distillation

Question 3

A solution is prepared by dissolving 10.0 g of NaCl (molar mass = 58.44 g/mol) in enough water to make 500 mL of solution. What is the molarity ($$M) of $$the solution?

Accepted Answer

$$M = \frac{10.0 \div 58.44}{0.5} = 0.342$$

Question 4

Which of the following is a characteristic of a homogeneous mixture?

Accepted Answer

Its composition is uniform throughout the mixture.

Question 5

A wine is labeled as '11.5% alcohol by volume.' How many milliliters of alcohol are present in a 750 mL bottle?

Accepted Answer

$$\frac{11.5}{100} 	imes 750 = 86.25 mL$$

Question 6

Which concentration unit is independent of temperature?

Accepted Answer

Molality ($$m)$$

Question 7

A solution is made by dissolving 32.0 g of CaCl$$_2 ($$molar mass = 110.98 g/mol) in 270 g of water. What is the molality ($$m) of $$the solution?

Accepted Answer

$$m = \frac{32.0 \div 110.98}{0.270} = 1.07$$

Question 8

Which of the following best explains why ionic compounds dissolve in water?

Accepted Answer

The hydration energy released when ions interact with water molecules overcomes the lattice energy of the ionic solid.

Question 9

What is the mole fraction ($$X) of $$ethanol in a solution containing 46.07 g of ethanol (C$$_2H$_5OH$$, molar mass = 46.07 g/mol) and 100.0 g of water (molar mass = 18.02 g/mol)?

Accepted Answer

$$X = \frac{1}{1 + 5.55} = 0.153$$

Question 10

Which statement about saturated solutions is correct?

Accepted Answer

A saturated solution contains the maximum amount of dissolved solute at equilibrium.

Question 11

According to Henry's Law, what happens to the solubility of a gas in a liquid as the partial pressure of the gas above the liquid increases?

Accepted Answer

The solubility increases.

Question 12

Which of the following is NOT a method for separating the components of a mixture?

Accepted Answer

Electrolysis

Question 13

A solution contains 300 g of H$$_2O$_2 ($$molar mass = 34.02 g/mol) and 700 g of water. What is the molality ($$m) of H$_2O$_2 in $$the solution?

Accepted Answer

$$m = \frac{300 \div 34.02}{0.7} = 12.6$$

Question 14

Which of the following best describes the entropy change when a solution forms?

Accepted Answer

The entropy of the solution is greater than the sum of the entropies of the pure solute and solvent.

Question 15

A solution is prepared by dissolving 24.3 g of glucose (C$$_6H$_{12}O$_6$$, molar mass = 180.16 g/mol) in 563 g of ethanol. What is the molality ($$m) of $$glucose in the solution?

Accepted Answer

$$m = \frac{24.3 \div 180.16}{0.563} = 0.239$$

Question 16

Which of the following statements about molarity ($$M) $$and molality ($$m) is $$correct?

Accepted Answer

Molarity varies with temperature, while molality does not.

Question 17

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

Concrete

Question 18

A solution is made by dissolving 6.24 g of CuSO$$_4$$·5H$$_2O ($$molar mass = 249.69 g/mol) in enough water to make 250 mL of solution. What is the molarity ($$M) of $$the solution?

Accepted Answer

$$M = \frac{6.24 \div 249.69}{0.25} = 0.1$$

Question 19

Which of the following factors does NOT affect the solubility of a solid in a liquid?

Accepted Answer

Pressure

Properties of Solutions: Composition, Types, and Concentration Units

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