Solutions and Colligative Properties: Freezing Point Depression & Concentration Units

What are colligative properties?

Properties that depend on the number of solute particles in a solution, not their identity.

What is freezing point depression?

The decrease in the freezing point of a solvent when a solute is added.

What is the formula for freezing point depression?

ΔT_f = i * K_f * m

What does 'i' represent in the freezing point depression formula?

The van't Hoff factor, which indicates the number of particles a solute dissociates into in solution.

What is the molal freezing point depression constant (K_f) for water?

1.86 °C/m

How do you calculate molality (m)?

Molality (m) = moles of solute / kilograms of solvent.

How do you find the new freezing temperature using freezing point depression?

Subtract the freezing point depression (ΔT_f) from the normal freezing point of the solvent.

What is the molar mass of potassium sulfate (K₂SO₄)?

174.27 g/mol

How do you calculate the molar mass of a non-ionic solute using freezing point depression?

Use the formula ΔT_f = i * K_f * m to find molality, then calculate moles and divide mass of solute by moles.

What is a solution?

A homogeneous mixture of two or more substances.

What is the difference between a solute and a solvent?

The solute is the minority component, while the solvent is the majority component of a solution.

What does 'likes dissolve likes' mean?

Polar substances dissolve in polar solvents, and non-polar substances dissolve in non-polar solvents.

What is entropy in the context of solutions?

A measure of disorder or dispersion of energy; systems tend to move towards higher entropy.

What are the three types of intermolecular forces involved in solution formation?

Solute-solute attractions, solvent-solvent attractions, and solute-solvent attractions.

What is a saturated solution?

A solution that has dissolved the maximum amount of solute at a given temperature.

How does temperature affect the solubility of most solids in liquids?

Solubility increases with increasing temperature.

How does temperature affect the solubility of gases in liquids?

Solubility decreases with increasing temperature.

What is Henry's Law?

It states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.

What is molarity (M)?

The concentration of a solution expressed as moles of solute per liter of solution.

What is molality (m)?

The concentration of a solution expressed as moles of solute per kilogram of solvent.

What is the formula for mass percentage of a solution?

(Mass of solute / Mass of solution) * 100%

What are parts per million (PPM) and parts per billion (PPB)?

Units used for very small concentrations; PPM = (Mass of solute / Mass of solution) * 10⁶, PPB = (Mass of solute / Mass of solution) * 10⁹.

What is mole fraction (X)?

The ratio of moles of solute to total moles of solute and solvent, expressed as a fraction.

How do you calculate the molarity of a solution?

Molarity (M) = moles of solute / liters of solution.

What is the enthalpy of solution (ΔH_soln)?

The overall energy change when a solute dissolves in a solvent, calculated as ΔH_soln = ΔH_solute + ΔH_solvent + ΔH_mixing.

What happens to the solubility of gases when the partial pressure increases?

The solubility of the gas increases.

What is the significance of the van't Hoff factor (i) for ionic compounds?

It is greater than 1 because ionic compounds dissociate into multiple particles in solution.

What is the effect of temperature on the solubility of sugar in tea?

Sugar dissolves more easily in hot tea than in cold tea.

What is the relationship between solute-solvent attractions and solution formation?

If solute-solvent attractions are stronger than solute-solute or solvent-solvent attractions, a solution will form.