Chapter 13: The Properties of Mixtures: Solutions and Colloids

A solute has a solubility in water of $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ solvent. Is this value the same as $\mathbf{21}\mathbf{g}\mathbf{/}\mathbf{kg}$ solution? Explain.

You want to convert among molarity, molality, and mole fraction of a solution. You know the masses of solute and solvent and the volume of solution. Is this enough information to carry out all the conversions? Explain.

When a solution is heated, which ways of expressing concentration change in value? Which remain unchanged? Explain.

Calculate the molarity of each aqueous solution:

1. 32.3 g of table sugar (${\mathbf{C}}_{\mathbf{12}}{\mathbf{H}}_{\mathbf{22}}{\mathbf{O}}_{\mathbf{11}}$) in 100. mL of solution
2. 5.80 g of ${\mathbf{LiNO}}_{\mathbf{3}}$ in 505 mL of solution.

Calculate the molarity of each aqueous solution:

1. 0.82 g of ethanol (${\mathbf{C}}_{\mathbf{2}}{\mathbf{H}}_{\mathbf{5}}\mathbf{OH}$) in 10.5 mL of solution
2. 1.27 g of gaseous ${\mathbf{NH}}_{\mathbf{3}}$ in 33.5 mL of solution.

Calculate the molarity of each aqueous solution:

(a) 78.0 mL of 0.240 M NaOH diluted to 0.250 L with water.

(b) 38.5 mL of 1.2 M ${\mathbf{HNO}}_{\mathbf{3}}$ diluted to 0.130 L with water.

Calculate the molarity of each aqueous solution:

(a) 25.5 mL of 6.25 M HCl diluted to 0.500 L with water

(b) 8.25 mL of $\mathbf{2}\mathbf{.}\mathbf{00}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{2}}\mathbf{M}$ KI diluted to 12.0 mL with water

: A biochemical engineer isolates a bacterial gene fragment and dissolves a $\mathbf{\text{10.0mg}}$sample in enough water to make $\mathbf{\text{30.0mL}}$of solution. The osmotic pressure of the solution is$\mathbf{\text{0.340torr}}$at $\mathbf{\text{25°C}}$.

(a) What is the molar mass of the gene fragment?

(b) If the solution density is$\mathbf{\text{0.997}}\raisebox{1ex}{${\displaystyle \mathbf{\text{g}}}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{\text{mL}}$}\right.$, how large is the freezing point depression for this solution (${\mathbf{\text{K}}}_{\mathbf{f}}$ of water is role="math" localid="1663657339191" ${\mathbf{\text{1.86}}}^{\mathbf{\text{o}}}\raisebox{1ex}{${\displaystyle \mathbf{\text{C}}}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{\text{m}}$}\right.$)?

Hexane and methanol are miscible as gases but only slightly soluble in each other as liquids. Explain.

How would you prepare the following aqueous solutions?

(a) 365 mL of $\mathbf{8}\mathbf{.}\mathbf{55}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{2}}\mathbf{M}$role="math" localid="1659271711435" ${\mathbf{KH}}_{\mathbf{2}}{\mathbf{PO}}_{\mathbf{4}}$from solid ${\mathbf{KH}}_{\mathbf{2}}{\mathbf{PO}}_{\mathbf{4}}$

(b) 465 mL of 0.335 M NaOH from 1.25 M NaOH.