GenChem 2 Quiz 2 Reviewer

Molarity

The number of moles of a solute in a given volume of solution in liters (L). Unit is in mol/L. Formula: M = mass of solute/FM/ L solution.

Molality

Of a solution is the number of moles of solute dissolved in 1 Kg of the solvent. Thus, if one gram molecule of a solute is present in 1 kg of the solvent, the concentration of solutions is said to be one molal. The unit of molarity is mol kg-1. Molality is the most convenient method to express the concentration of solutions because it involves the mass of liquids rather than their volumes. It is also independent of the variation in temperature. Formula: m = mass of solute/FM/mass of solvent.

Normality

Defined as equivalent weight per liter solution. Unit is eq wt/ L. Formula: N = mass of solute/FM solute / f/ L solution

Dilution

is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to a solution. To do that to a solution means to add more solvent without the addition of more solute. It is used to calculate the amount of original solution needed to prepare a less concentrated solution.

Formula: C1V1 = C2V2

Freezing Point Depression

addition of solutes in a liquid to form a solution results in the solute particles interfering with the formation of stronger IMF in the liquid which results in a lower freezing point.                         

Formula: △t_f = K_fm (A change in freezing point = freezing point constant x molality)

Vapor Pressure Lowering

Interference of solute particles in a liquid prevents the molecules of the liquid to easily vaporize.

Boiling Point Elevation

lower vapor pressure results in higher boiling point, solutions are heated to a higher temperature to supply the additional KE needed to raise the vapor pressure to atmospheric pressure.

Formula: △T_b = K_bm