Q: Calculate the mass percent of KBr in a solution prepared by dissolving 51.0 g of KBr in 310 g of water.

$$ \frac{51.0}{51.0 + 310} \times 100\% = 14.1\% $$

Q: What is the molarity of a solution prepared by dissolving 23.7 g NaOH (MW = 40.00 g/mol) in enough water to make 2.50 L of solution?

$$ M = \frac{23.7 \text{ g} / 40.00 \text{ g/mol}}{2.50 \text{ L}} = 0.237 \text{ M} $$

Q: A solution is prepared by dissolving 43.0 g KClO3 (MW = 122.55 g/mol) in enough water to make 100.0 mL of solution. If the density of the solution is 1.760 g/mL, what is the molality?

$$ \text{Molality} = \frac{43.0 / 122.55}{0.1760 - 0.0430} = 2.44 \text{ m} $$

Q: What is the boiling point of a 3.71 m aqueous CaBr2 solution? (Assume $$i = 3$$, $$K_b = 0.51 \ ^\circ \text{C}/m$$ for water, $$T_b^0$ = 100.0 ^\circ \text{C})$$

$$ T_b = 100.0 + (3 \times 0.51 \times 3.71) = 105.7 ^\circ \text{C} $$

Question 1

Which of the following best describes a solution?

Accepted Answer

A homogeneous mixture of two or more substances with uniform composition.

Question 2

A student dissolves 10.0 g of NaCl in 500.0 mL of water. Identify the solute and solvent.

Accepted Answer

Solute: 10.0 g NaCl; Solvent: 500.0 mL water

Question 3

Which of the following mixtures is a colloid?

Accepted Answer

Milk

Question 4

According to the theory of solubility, which of the following pairs will most likely form a solution?

Accepted Answer

CH3OH and H2O

Question 5

Calculate the mass percent of KBr in a solution prepared by dissolving 51.0 g of KBr in 310 g of water.

Accepted Answer

$$ \frac{51.0}{51.0 + 310} 	imes 100\% = 14.1\% $$

Question 6

What is the molarity of a solution prepared by dissolving 23.7 g NaOH (MW = 40.00 g/mol) in enough water to make 2.50 L of solution?

Accepted Answer

$$ M = \frac{23.7 	ext{ g} / 40.00 	ext{ g/mol}}{2.50 	ext{ L}} = 0.237 	ext{ M} $$

Question 7

Which of the following solutions will have the highest concentration of bromide ions?

Accepted Answer

0.10 M AlBr3

Question 8

A solution is prepared by dissolving 43.0 g KClO3 (MW = 122.55 g/mol) in enough water to make 100.0 mL of solution. If the density of the solution is 1.760 g/mL, what is the molality?

Accepted Answer

$$ 	ext{Molality} = \frac{43.0 / 122.55}{0.1760 - 0.0430} = 2.44 	ext{ m} $$

Question 9

Which of the following compounds will have the largest value for the Van’t Hoff factor (i)?

Accepted Answer

AlCl3

Question 10

What is the boiling point of a 3.71 m aqueous CaBr2 solution? (Assume $$i = 3$$, $$K_b = 0.51 \ ^\circ 	ext{C}/m$$ for water, $$T_b^0$ = 100.0 ^\circ 	ext{C})$$

Accepted Answer

$$ T_b = 100.0 + (3 	imes 0.51 	imes 3.71) = 105.7 ^\circ 	ext{C} $$

Question 11

A red blood cell placed in pure water will swell because:

Accepted Answer

The osmotic pressure is greater in the cell than in the water.

Question 12

Which of the following best describes osmosis?

Accepted Answer

The movement of water molecules across a semipermeable membrane into a region of high solute concentration.

Question 13

If the fluid surrounding a patient’s red blood cells is depleted in electrolytes, is crenation or hemolysis more likely to occur?

Accepted Answer

Hemolysis

Question 14

Which of the following solutions is isotonic to blood?

Accepted Answer

A solution with the same osmotic pressure as blood

Question 15

What is the effect on the solubility of a gas in water as temperature increases?

Accepted Answer

The solubility of the gas decreases.

Question 16

A solution is prepared by dissolving 30.00 mL of benzene (C6H6, density = 0.8787 g/mL) in dichloromethane to make a final volume of 750.0 mL. What is the molarity of benzene?

Accepted Answer

$$ M = \frac{30.00 	imes 0.8787 / 78.11}{0.7500} = 0.451 	ext{ M} $$

Question 17

Which of the following compounds will have the highest boiling point?

Accepted Answer

0.25 M NH4NO3

Question 18

Which of the following statements about Henry’s Law is correct?

Accepted Answer

The solubility of a gas is directly proportional to the partial pressure of the gas above the liquid.

Introductory Chemistry: Solutions and Their Properties

Guida di studio - Domande di pratica

Study guide - Flashcard