General Chemistry 2: Chapter 11

What is molarity (M)?

(moles of solute) / (liters of solution)

What is mass percent?

((mass of solute) / (mass of solution)) x 100%

What is mole fraction?

(moles) / (total moles of solution)

What is molality (m)?

(moles of solute) / (kilogram of solvent)

What are the steps in the formation of a liquid solution?

• Step 1: Expanding the solute

• Step 2: Expanding the solvent

• Step 3: Allowing the solute and solvent to interact to form the solution

Provide an energy breakdown of this process.

• Steps 1 and 2 require energy (endothermic)

• Step 3 releases energy (exothermic)

What is the enthalpy (heat) of solution?

Enthalpy change associated wtih the formation of the solution is the sum of the delta H values for the steps

What are the factors affecting solubility?

• Structure (polarity)

• Pressure (Henry’s law)

• Temperature (affecting aqueous solutions)

Which substances are hydrophobic, and which are hydrophilic?

• Hydrophobic: non-polar substances

• Hydrophilic: polar substances

How does pressure have an effect on the solubility of a substance?

Amount of gas dissolved in a solution is directly proportional to the pressure of the gas above the solution

What is normality?

For an acid: (protons in the acid) x (molarity)
For a base: (hydroxide ions in the base) x (molarity)

How does temperature affect solubility?

Higher temperature means higher solubility, with the notable exception that solubility of a gas in solvent typically decreases with increasing temperature

What does Raoult’s Law state?

(Observed vapor pressure of solution) = (mole fraction of solvent)(vapor pressure of pure solvent)

What are colligative properties?

Depend only on the number, not on the identity, of the solute in an ideal solution

What are some examples of colligative properties?

• Boiling-point elevation

• Freezing-point depression

• Osmotic pressure

How does the addition of a nonvolatile solute affect the boiling point of a solute?

Nonvolatile solute elevates the boiling point of the solvent

What happens to the freezing point of a solution when a solute is dissolved in a solvent?

The freezing point becomes lower than that of the pure solvent

What is van’t Hoff Factor (i)?

The relationship between the moles of solute dissolved and the moles of particles in solution is usually ex

What is osmosis?

Flow of solvent into the solution through a semipermeable membrane

What is a colloid?

A suspension of tiny particles in some medium

What is coagulation?

• Destruction of a colloid

• Usually accomplished either by heating or by adding an electrolyte