Q: Calculate the mass percent (% m/m) of Na2CO3 in a solution prepared by mixing 15.0 g of Na2CO3 and 235 g of H2O.

$$\frac{15.0\ \text{g}}{250\ \text{g}} \times 100 = 6.00\%$$

Q: What is the molarity of a solution prepared by dissolving 34.8 g of KNO3 in enough water to make 0.225 L of solution? (Molar mass of KNO3 = 101.11 g/mol)

$$\frac{34.8\ \text{g}}{101.11\ \text{g/mol}} = 0.344\ \text{mol}$$; $$\frac{0.344\ \text{mol}}{0.225\ \text{L}} = 1.53\ \text{M}$$

Q: What is the final concentration when 0.50 L of 6.0 M HCl solution is diluted to a final volume of 1.0 L?

$$C_1V_1 = C_2V_2$$; $$6.0\ \text{M} \times 0.50\ \text{L} = C_2$ \times 1.0\ \text{L}$$; $$C_2 = 3.0$$\ \text{M}$$

Q: How many grams of NaOH are needed to prepare 75.0 g of a 14.0% (m/m) NaOH solution?

$$75.0\ \text{g} \times \frac{14.0\ \text{g NaOH}}{100\ \text{g solution}} = 10.5\ \text{g NaOH}$$

Q: How many mL of 3.00 M HCl are needed to completely react with 4.85 g of CaCO3? (Molar mass CaCO3 = 100.1 g/mol)

$$4.85\ \text{g} \times \frac{1\ \text{mol}}{100.1\ \text{g}} \times \frac{2\ \text{mol HCl}}{1\ \text{mol CaCO3}} \times \frac{1000\ \text{mL}}{3.00\ \text{mol HCl}} = 32.3\ \text{mL}$$

Question 1

A dialysis patient is experiencing side effects due to her body's inability to regulate water in her cells. Which of the following best explains the chemical principle behind this phenomenon?

Accepted Answer

The concentration of electrolytes and the rate at which waste products are removed from her body affect the movement of water across cell membranes.

Question 2

Which of the following statements about solutions is correct?

Accepted Answer

A solution is a homogeneous mixture of two or more substances where the solute is present in a smaller amount than the solvent.

Question 3

Which of the following combinations will form a solution according to the 'like dissolves like' principle?

Accepted Answer

Polar solute and polar solvent

Question 4

When NaCl dissolves in water, what happens at the molecular level?

Accepted Answer

Na+ ions are attracted to the oxygen atom (δ−) of water, and Cl− ions are attracted to the hydrogen atom (δ+) of water.

Question 5

Which of the following is a strong electrolyte in aqueous solution?

Accepted Answer

Na2SO4

Question 6

Calculate the mass percent (% m/m) of Na2CO3 in a solution prepared by mixing 15.0 g of Na2CO3 and 235 g of H2O.

Accepted Answer

$$\frac{15.0\ 	ext{g}}{250\ 	ext{g}} 	imes 100 = 6.00\%$$

Question 7

What is the molarity of a solution prepared by dissolving 34.8 g of KNO3 in enough water to make 0.225 L of solution? (Molar mass of KNO3 = 101.11 g/mol)

Accepted Answer

$$\frac{34.8\ 	ext{g}}{101.11\ 	ext{g/mol}} = 0.344\ 	ext{mol}$$; $$\frac{0.344\ 	ext{mol}}{0.225\ 	ext{L}} = 1.53\ 	ext{M}$$

Question 8

A nurse prepares an IV bag with a 0.9% (m/v) NaCl solution. What type of solution is this relative to red blood cells?

Accepted Answer

Isotonic

Question 9

Which of the following best describes a colloid?

Accepted Answer

A mixture with medium-sized particles that do not settle out and cannot pass through a semipermeable membrane.

Question 10

What is the final concentration when 0.50 L of 6.0 M HCl solution is diluted to a final volume of 1.0 L?

Accepted Answer

$$C_1V_1 = C_2V_2$$; $$6.0\ 	ext{M} 	imes 0.50\ 	ext{L} = C_2$ 	imes 1.0\ 	ext{L}$$; $$C_2 = 3.0$$\ 	ext{M}$$

Question 11

How many grams of NaOH are needed to prepare 75.0 g of a 14.0% (m/m) NaOH solution?

Accepted Answer

$$75.0\ 	ext{g} 	imes \frac{14.0\ 	ext{g NaOH}}{100\ 	ext{g solution}} = 10.5\ 	ext{g NaOH}$$

Question 12

Which of the following solutions will cause crenation of red blood cells?

Accepted Answer

A 2% NaCl solution

Question 13

A solution is prepared by mixing 60.0 mL of ethyl alcohol and 30.0 mL of methyl alcohol. Which is the solute?

Accepted Answer

Methyl alcohol

Question 14

Which of the following best explains why fish die in water that is too warm?

Accepted Answer

Oxygen gas is less soluble in warm water, so fish cannot obtain enough O2 for survival.

Question 15

How many mL of 3.00 M HCl are needed to completely react with 4.85 g of CaCO3? (Molar mass CaCO3 = 100.1 g/mol)

Accepted Answer

$$4.85\ 	ext{g} 	imes \frac{1\ 	ext{mol}}{100.1\ 	ext{g}} 	imes \frac{2\ 	ext{mol HCl}}{1\ 	ext{mol CaCO3}} 	imes \frac{1000\ 	ext{mL}}{3.00\ 	ext{mol HCl}} = 32.3\ 	ext{mL}$$

Question 16

Which of the following best describes osmosis?

Accepted Answer

Water flows from a lower to a higher solute concentration across a semipermeable membrane.

Question 17

What is the osmolarity of a 0.10 M Na2CO3 solution?

Accepted Answer

$$0.10\ 	ext{M} 	imes 3 = 0.30\ 	ext{osmolar}$$

Chapter 9: Solutions – Properties, Types, and Calculations

Guida di studio - Domande di pratica

Study guide - Flashcard