Q: A 5.0% (m/v) glucose solution is commonly used intravenously. If the molar mass of glucose is 180 g/mol, what is the osmolarity of this solution?

$$\displaystyle \frac{5.0\ \mathrm{g}}{100\ \mathrm{mL}} \times \frac{1000\ \mathrm{mL}}{1\ \mathrm{L}} = 50\ \mathrm{g/L}$$; $$\displaystyle \frac{50\ \mathrm{g/L}}{180\ \mathrm{g/mol}} = 0.28\ \mathrm{osmol/L}$$

Q: A saline solution contains 1.5% (m/v) NaCl. How many grams of NaCl are needed to prepare 250 mL of this solution?

$$\displaystyle \text{Mass} = \frac{1.5}{100} \times 250 = 3.75\ \mathrm{g}$$

Question 1

Which of the following best describes a colloid?

Accepted Answer

A homogeneous mixture with particle sizes between 2 and 500 nm that does not separate on standing and is often murky or opaque to light.

Question 2

Which of the following pairs of substances is most likely to form a solution based on their intermolecular forces?

Accepted Answer

Hexane (C6H14) and carbon tetrachloride (CCl4)

Question 3

A solution is prepared by dissolving 2.355 g of H2SO4 (molar mass = 98.1 g/mol) in water and diluting to a final volume of 50.0 mL. What is the molarity of the solution?

Accepted Answer

$$\displaystyle \frac{2.355\ \mathrm{g}}{98.1\ \mathrm{g/mol}} = 0.0240\ \mathrm{mol}$$; $$\displaystyle \frac{0.0240\ \mathrm{mol}}{0.0500\ \mathrm{L}} = 0.480\ \mathrm{M}$$

Question 4

Which of the following statements about the effect of temperature on solubility is correct?

Accepted Answer

The solubility of most solids increases with increasing temperature, while the solubility of gases decreases with increasing temperature.

Question 5

A 5.0% (m/v) glucose solution is commonly used intravenously. If the molar mass of glucose is 180 g/mol, what is the osmolarity of this solution?

Accepted Answer

$$\displaystyle \frac{5.0\ \mathrm{g}}{100\ \mathrm{mL}} 	imes \frac{1000\ \mathrm{mL}}{1\ \mathrm{L}} = 50\ \mathrm{g/L}$$; $$\displaystyle \frac{50\ \mathrm{g/L}}{180\ \mathrm{g/mol}} = 0.28\ \mathrm{osmol/L}$$

Question 6

Which of the following best explains why adding salt to ice causes the ice to melt at a lower temperature?

Accepted Answer

The dissolved salt particles lower the freezing point of water, a phenomenon known as freezing-point depression.

Question 7

A solution is prepared by diluting 75 mL of a 3.5 M glucose solution to a final volume of 450 mL. What is the final concentration?

Accepted Answer

$$\displaystyle M_d = \frac{M_c V_c}{V_d} = \frac{(3.5\ \mathrm{M})(75\ \mathrm{mL})}{450\ \mathrm{mL}} = 0.58\ \mathrm{M}$$

Question 8

Which of the following is a strong electrolyte?

Accepted Answer

Sodium chloride (NaCl) in water

Question 9

A saline solution contains 1.5% (m/v) NaCl. How many grams of NaCl are needed to prepare 250 mL of this solution?

Accepted Answer

$$\displaystyle 	ext{Mass} = \frac{1.5}{100} 	imes 250 = 3.75\ \mathrm{g}$$

Question 10

Which of the following best describes the process of osmosis?

Accepted Answer

The movement of solvent molecules through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Question 11

A patient receives an intravenous solution that is hypotonic relative to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Water will enter the cells, causing them to swell and possibly burst.

Question 12

Which equation correctly expresses Henry’s Law for the solubility of a gas in a liquid?

Accepted Answer

$$\displaystyle \frac{C_1$}{P_1$} = \frac{C_2$}{P_2$}$$

Question 13

A solution is made by dissolving 0.75 mol of KBr in 1.0 kg of water. What is the boiling point of the solution? (Assume KBr is a strong electrolyte and the boiling point elevation constant for water is $$0.51\ ^\circ\mathrm{C}/\mathrm{mol})$$

Accepted Answer

$$100.77\ ^\circ\mathrm{C}$$

Question 14

Which of the following is an example of a colligative property?

Accepted Answer

Boiling point elevation

Question 15

A 1.50 L solution has an osmolarity of 0.300 osmol/L. How many grams of NaCl (molar mass = 58.44 g/mol) are needed to prepare this solution? (NaCl dissociates into 2 ions)

Accepted Answer

$$\displaystyle 	ext{Molarity} = \frac{0.300\ \mathrm{osmol/L}}{2} = 0.150\ \mathrm{mol/L}$$; $$0.150\ \mathrm{mol/L} 	imes 1.50\ \mathrm{L} = 0.225\ \mathrm{mol}$$; $$0.225\ \mathrm{mol} 	imes 58.44\ \mathrm{g/mol} = 13.1\ \mathrm{g}$$

Question 16

Which of the following best describes dialysis as used in medicine?

Accepted Answer

A process in which small solute particles and solvent molecules pass through a semipermeable membrane, but large molecules like proteins do not.

Question 17

A sample of 18-carat gold contains 18 g of gold in 24 g of metal. What is the mass of gold in a 5.05 g ring made of 18-carat gold?

Accepted Answer

$$\displaystyle (5.05\ \mathrm{g}) \left(\frac{18}{24}\right) = 3.79\ \mathrm{g}$$

Solutions and Their Properties: General Chemistry Study Notes

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