Q: A chemist wants to prepare 250 mL of a 0.50 M NaCl solution. How many grams of NaCl (molar mass = 58.44 g/mol) are needed?

$$0.50 \times 0.250 \times 58.44 = 7.305 g$$

Q: A student wants to dilute 20.0 mL of a 2.0 M HCl solution to a final concentration of 0.50 M. What will be the final volume after dilution?

$$V_2$$ = \frac{M_1V_1}{$$M_2$$} = \frac{2.0 \times 20.0}{0.50} = 80.0$$ mL

Q: A solution is prepared by dissolving 13.7 g of glucose ($$C_6H_{12}O_6$) in 0.86 kg of water. If K_b$ for water is 0.512$$ \, ^\circ C \cdot kg/mol$$, what is the boiling point of the solution? (Molar mass of glucose = 180 g/mol)

$$T_2 = 100.00 + (0.088$$ \times 0.512) = 100.05 \, ^\circ C$$

Question 1

Which of the following best describes the mixture shown in the first image (a glass of water with a straw)?

Accepted Answer

A homogeneous solution because the water is clear and uniform throughout.

Question 2

The second image shows oil and water in a test tube. What term best describes this system?

Accepted Answer

Immiscible liquid-liquid mixture

Question 3

In the third image, crystals are forming in a solution. What process is most likely occurring?

Accepted Answer

A supersaturated solution is being cooled, causing crystallization.

Question 4

The fourth image shows a string with crystals growing on it. What is the role of the string in this process?

Accepted Answer

It provides a seeding surface for crystallization in a supersaturated solution.

Question 5

Based on the fifth image (cartoon of the Earth sweating under the sun), which of the following statements is correct regarding the solubility of gases in water as temperature increases?

Accepted Answer

Solubility of gases in water decreases as temperature increases.

Question 6

The sixth image shows smoke coming from factory chimneys. Which concentration unit would be most appropriate to express the amount of a pollutant in the air?

Accepted Answer

Parts per million (ppm)

Question 7

The seventh image shows cans and bottles of soda. Which type of solution is represented by the gas dissolved in the liquid soda?

Accepted Answer

Gas in liquid

Question 8

Refer to the eighth image (solubility of a gas vs. pressure). According to Henry's Law, what happens to the solubility of a gas in a liquid as pressure increases?

Accepted Answer

It increases.

Question 9

A chemist wants to prepare 250 mL of a 0.50 M NaCl solution. How many grams of NaCl (molar mass = 58.44 g/mol) are needed?

Accepted Answer

$$0.50 	imes 0.250 	imes 58.44 = 7.305 g$$

Question 10

Which of the following best describes the mixture in the tenth image (a can of paint)?

Accepted Answer

Colloid

Question 11

The eleventh image shows a carton of milk. Milk is best classified as which type of mixture?

Accepted Answer

Colloid (emulsion)

Question 12

The twelfth image shows smoke. Which of the following statements about colloids is correct?

Accepted Answer

Colloids scatter light due to the Tyndall effect.

Question 13

A student wants to dilute 20.0 mL of a 2.0 M HCl solution to a final concentration of 0.50 M. What will be the final volume after dilution?

Accepted Answer

$$V_2$$ = \frac{M_1V_1}{$$M_2$$} = \frac{2.0 	imes 20.0}{0.50} = 80.0$$ mL

Question 14

Which of the following best explains why colloidal particles do not settle out of solution?

Accepted Answer

They are kept apart by surrounding water molecules and repulsion of like charges.

Question 15

A solution is prepared by dissolving 13.7 g of glucose ($$C_6H_{12}O_6$) in 0.86 kg of water. If K_b$ for water is 0.512$$ \, ^\circ C \cdot kg/mol$$, what is the boiling point of the solution? (Molar mass of glucose = 180 g/mol)

Accepted Answer

$$T_2 = 100.00 + (0.088$$ 	imes 0.512) = 100.05 \, ^\circ C$$

Question 16

Which of the following is an example of a suspension?

Accepted Answer

Sand in water

Question 17

Which of the following best describes the Tyndall effect?

Accepted Answer

The scattering of light by particles in a colloid.

Question 18

A 1.50 M solution of $$Na_3PO_4 is $$prepared. What is the molarity of $$Na^+$$ ions in the solution?

Accepted Answer

$$4.50 M$$

Question 19

Which of the following statements about 'like dissolves like' is correct?

Accepted Answer

Polar solvents dissolve polar solutes.

Chapter 5: Solutions – Properties, Types, and Calculations

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