Chem Chapter 13: Properties of Mixtures

Solvent

what something is dissolved in

Solute

the thing being dissolved

Solubility

the max amount of a solute that can dissolve in a certain amount of a solvent

Like dissolves like

substances with similar intermolecular forces will dissolve in each other

Name the 6 intermolecular forces in solutions

1. Ion-dipole forces

2. Ion-induced ion-dipole forces

3. Hydrogen bonding

4. Dipole forces

5. Dipole-induced dipole forces

6. London dispersion forces

Enthalpy of Solutions

Enthalpy of Solvent + Solute + Mix

Exdothermic changes of Enthalpies of Solutions

Enthalpy of Solution < 0

enthalpy of solute + solvent < enthalpy of mix

it takes less energy to separate molecules in the solute and solvent

Endothermic changes of Enthalpies of Solutions

Enthalpy of Solution > 0

Enthalpy of solute + solvent > Enthalpy of mix

it takes more energy to seperate particles in the solute and solvent

Steps and Enthalpies needed to form solutions

1. Solute particles separate → Endothermic

   a. Solute + heat → Solute (seperate)

   b. enthalpy of solute > 0

2. Solvent particles seperate → Endothermic

   a. solvent + heat → Solvent (seperate)

   b. enthalpy of solvent > 0

3. Solvent and Solute particles mix → Exothermic

   a. solvent + solute → solution + heat

   b.enthalpy of mix < 0

Solvation

surrounding solute particles with the solvent

Enthalpy of Solvation = Enthalpy of Solvent + Enthalpy of Mix

Hydration

solvation in water needed to break ionic compounds

Enthalpy of Hydration = Enthalpy of solution - Enthalpy of solute

Charge density

ratio of charge to volume → inversely proportional to Enthalpy of Hydration

High charge + Small size = Greater density

Increases across periods and decreases down groups

Entropy

how many ways a system can distribute energy of particles

S gas > S liquid > S solid

Enthalpy of Entropy

+ when particles gain movement and - when particles lose it

solutions have more S than pure substances

Saturated solutions

EQUILIBRIUM REACHED!!

Unsaturated solutions

not enough solute in the solvent

Supersatured solutions

too much solute and not enough solvent

Henry’s law

S gas = k(H) * P(gas)

gas solubility is directly proportional to the partial pressure

Molarity

mol Solute/ L solution

MOLALITY

mol solute / kg solvent

Electrolytes

particles seperate into ions when dissolved in water

Vapor pressure lowering

P solvent = X solv. * P pure solvent

P pure solvent - P solvent = Enthalpy Pressure

Boiling point elevation

Enthalpy of boiling point = Kb * m

m = MOLALITY

Freezing point depression

Enthalpy of freezing point = Kf * m

FP solution = FP solvent - Enthalpy of FP