Chemistry Solutions: Types, Concentration & Colligative Properties: 18 MCQs with answers

B · A homogeneous mixture of two or more substances

A solution is a homogeneous mixture where solute and solvent are uniformly mixed at the particle level.

A · Water

Water is the solvent because it does the dissolving and is present in the greater amount.

D · Particles are at the molecular or ionic level, typically <1 nm

Solutions have particles smaller than 1 nm, so they do not scatter light significantly or settle.

B · Like dissolves like

The general rule is 'like dissolves like': polar solvents dissolve polar/ionic solutes, nonpolar dissolve nonpolar.

B · Air

Air is a solution of gases, mainly nitrogen and oxygen.

A · True

A solution is a homogeneous mixture where solute particles are dispersed at the molecular or ionic level, typically smaller than 1 nanometer.

A · Saturated

A saturated solution has dissolved as much solute as possible at that temperature; excess solute will not dissolve.

D · It increases

For most solids, solubility increases with temperature.

D · Gas solubility decreases as temperature increases

The solubility of gases decreases with increasing temperature, so carbon dioxide escapes faster from warm soda.

C · $M = \frac{\text{moles of solute}}{\text{liters of solution}}$

Molarity is defined as moles of solute per liter of solution.

A · 5%

Mass percent = (5 g / 100 g) × 100% = 5%.

C · Oil is nonpolar and water is polar, so they cannot form favorable interactions

Oil is nonpolar and water is polar; the mismatch means oil molecules cluster together rather than mix with water.

C · Surrounded by water molecules through hydrogen bonding

Molecular solutes like sugar separate and become surrounded by water molecules via hydrogen bonding; dissolving is not melting.

A · Supersaturated and unstable

A supersaturated solution contains excess solute and is unstable; it can crystallize suddenly if disturbed.

A · Water, because it is present in the greater amount

The solvent is usually the component present in the greater amount; here water is 90 mL vs ethanol 10 mL.

B · Dissolving is dispersal of solute particles in a solvent; melting is a change of state due to heat

Dissolving disperses solute particles into a solvent without changing state; melting is a solid-to-liquid phase change caused by heat.

B · 0.67 M

To find the molarity (M), use the formula: $$M = \frac{\text{moles of solute}}{\text{liters of solution}}$$. First, calculate moles of KCl: $$\text{moles} = \frac{10 \text{ g}}{74.55 \text{ g/mol}} \approx 0.134 \text{ mol}$$. Convert 500 mL to liters: $$500 \text{ mL} = 0.500 \text{ L}$$. Thus,…

B · 20%

To find the mass percent, use the formula: $$\text{mass percent} = \left( \frac{\text{mass of solute}}{\text{mass of solution}} \right) \times 100\%$$. The mass of the solution is $$20 \text{ g (sugar)} + 200 \text{ g (water)} = 220 \text{ g}$$. Thus,…