# Unit 7: Chemical Equilibrium

## 7.13 pH and Solubility

The solubility of some salts is affected by the pH of the environment Basic Solutions High pH (more basic) → more OH- ions         ○ Ex:           ■ Increasing pH (adding OH-) → Q > Ksp → decreases solubility of the salt → solubility is less in a basic environment...

## 7.12 Common-Ion Effect

Common-Ion Effect: when you try to dissolve the solid in a solution with either the cation or anion already present less solid will dissolve/more solid will be produced → the solubility of that salt is going to be less that it was in pure water            ○ Q > Ksp...

## 7.11 Introduction to Solubility Equilibria

For solids dissolving to form aqueous solutions          ○ Ksp = solubility product constant =                     ■ Ksp value depends on ion concentration → more cations & anions = higher value                     ■ Solids not included in equilibrium expression...

## 7.10 Reaction Quotient and Le Chateilier’s Principle

A disturbance to a system at equilibrium causes Q to differ from K The reaction will “shift” to bring Q back into agreement with K Effects of Changes to a System You can change the position of equilibrium, but not the actual value of equilibrium (K) Pressure (only...

## 7.9 Introduction to Le Chatelier’s Principle

Le Chatelier’s Principle: if a system at equilibrium is changed, the position of the equilibrium will shift in the direction that tends to reduce that change

## 7.7 Calculating Equilibrium Concentrations

Type 1: Given initial concentrations and one equilibrium concentration Write balanced, dissolution equation → Set up ICE Table below         ○ I: initial concentrations         ○ C: Change in concentration        ○ E: Equilibrium concentrations Solve for x If question...

## 7.6 Properties of the Equilibrium Constant

The equilibrium constant of the reverse reaction is the reciprocal of the K value of the forward reaction          ○ Ex: Forward reaction:  (flip it) Reverse Reaction:   When the equation for a reaction is multiplied by n,         ○ Ex: mult. by factor of 2: When...

## 7.5 Magnitude of the Equilibrium Constant

Use the magnitude of K to justify if a reaction favors the products or reactants at equilibrium K >1 products (forward reaction) are favored at equilibrium; more products than reactants                ○ If K is VERY large, reaction goes essentially to completion  ...

## 7.4 Calculating the Equilibrium Constant

Equilibrium problems often include temperature → not needed in order to calculate K            ○ K is a CONSTANT that only changes with temperature “Saturated solution” is at equilibrium

## 7.3 Reaction Quotient and Equilibrium Constant

For the Equilibrium Constant Expression relates the concentrations of reactants and products once the reaction has reached equilibrium.  ○ Equilibrium Constant Expression:                     ○ In questions, the equilibrium constant expression can be written as Kc, or...