Chapter 12 Chemistry Notes: Solutions:
Sec 12.1: Thirsty Solutions: Why You Shouldn’t Drink Seawater:
Solution-a homogenous mixture of two or more substances or components
Solvent-the majority component of a solution
Solute-the minority component of a solution
Sec 12.2: Types of Solutions and Solubility:
Solubility-the amount of the substance that will dissolve in a given amount of solvent
Entropy-a measure of energy randomization or energy dispersion in a system
Sec 12.3: Energetics of Solution Formation:
Three Steps of Solution Formation:
1.) Separating the solute into its constituent particles
*Note: always positive ∆H (endothermic) because energy is required to
overcome the forces holding the solute together
2.) Separating the solvent particles from each other to make room for the solute
particles
*Note: Always positive ∆H (endothermic) because energy is required to
overcome the intermolecular forces that hold the solvent together
3.) Mixing the solute particles with the solvent particles
*Note: Always negative (exothermic) because energy is released as the solute
particles interact with solvent particles
Enthalpy of Solution ( ∆H soln)-the overall enthalpy change upon solution formation
is the sum of the changes in enthalpy
∆H soln = ∆H solute + ∆H solvent + ∆H mix
+ + -
Heat of Hydration ( ∆H hydration)- ∆H solvent and ∆H mix can be combine into this,
this is the enthalpy change that occurs when 1 mole of the gaseous solute is dissolved
in water
*Note: ∆H hydration is always largely negative (exothermic) for ionic compounds
Sec 12.4: Solution Equilibrium and Factors Affecting Solubility:
Dynamic Equilibrium-the rates of dissolution and recrystallization become equal
Saturated Solution-A solution in which the dissolved solute is in dynamic equilibrium
with the solid (dissolved) solute
Unsaturated Solution-A solution containing less than the equilibrium amount of solute
Supersaturated Solution-one containing more than the equilibrium amount of solute
Henrys Law-shows that the solubility of a gas in a liquid is directly proportional to the
pressure of the gas above the liquid
Sec 12.1: Thirsty Solutions: Why You Shouldn’t Drink Seawater:
Solution-a homogenous mixture of two or more substances or components
Solvent-the majority component of a solution
Solute-the minority component of a solution
Sec 12.2: Types of Solutions and Solubility:
Solubility-the amount of the substance that will dissolve in a given amount of solvent
Entropy-a measure of energy randomization or energy dispersion in a system
Sec 12.3: Energetics of Solution Formation:
Three Steps of Solution Formation:
1.) Separating the solute into its constituent particles
*Note: always positive ∆H (endothermic) because energy is required to
overcome the forces holding the solute together
2.) Separating the solvent particles from each other to make room for the solute
particles
*Note: Always positive ∆H (endothermic) because energy is required to
overcome the intermolecular forces that hold the solvent together
3.) Mixing the solute particles with the solvent particles
*Note: Always negative (exothermic) because energy is released as the solute
particles interact with solvent particles
Enthalpy of Solution ( ∆H soln)-the overall enthalpy change upon solution formation
is the sum of the changes in enthalpy
∆H soln = ∆H solute + ∆H solvent + ∆H mix
+ + -
Heat of Hydration ( ∆H hydration)- ∆H solvent and ∆H mix can be combine into this,
this is the enthalpy change that occurs when 1 mole of the gaseous solute is dissolved
in water
*Note: ∆H hydration is always largely negative (exothermic) for ionic compounds
Sec 12.4: Solution Equilibrium and Factors Affecting Solubility:
Dynamic Equilibrium-the rates of dissolution and recrystallization become equal
Saturated Solution-A solution in which the dissolved solute is in dynamic equilibrium
with the solid (dissolved) solute
Unsaturated Solution-A solution containing less than the equilibrium amount of solute
Supersaturated Solution-one containing more than the equilibrium amount of solute
Henrys Law-shows that the solubility of a gas in a liquid is directly proportional to the
pressure of the gas above the liquid
