Chapter 9: Chemical Equilibrium

If K is < 1

Reaction favors reactants

There will be more reactants than products at equilibrium

If K is > 1

Reaction favors products

There will be more products than reactants at equilibrium

If Q > K

The reaction has more products and fewer reactants than at equilibrium

To reach equilibrium, the reaction will shift left, toward the reactants

If Q < K

The reaction has fewer products and more reactants than the equilibrium

To reach equilibrium, the reaction will shift right, toward the products

What does Le Chatelier’s principle say?

when a system at equilibrium is subjected to a change, the system will shift in a direction that counteracts the imposed change in order to restore equilibrium

For exothermic reactions;

when heat is added to the reaction….

when heat is removed….

Its like adding a product
Its like removing products

If heat is added to a reaction (increasing temperature)…

Its like adding a product so reactants shift to the left

If heat is removed (decreasing temperature)…

Its the same as removing one of the products and the reaction will proceed to the right

For endothermic reactions:

when heat is added to the reaction….

when heat is removed….

Its like adding a reactant
Its like removing reactants

As volume decreases what happens to pressure?

Pressure increases

As volume decreases (or pressure increases)….

there is less available space for the gas particles and gas concentrations increase and so the equilibrium shifts toward the side with fewer total mole of gas

What are electrolytes?

Substances that produce ions when dissolved in water

What are strong electrolytes?

Strong acids, strong bases, and highly soluble ionic compounds

Strong electrolytes usually…

Dissociate entirely in solution

Molar solubility is related to Ksp and it represents what?

The amount of solute that disso

lves per liter os solution at equilibrium

Ionic compounds with small K_spvalues are________ and therefore ________ to form precipitates

Less soluble and more likely to form precipitates

If Q_sp is greater than K_sp

Precipitate will occur

If Q_sp is less than K_sp

Precipitate will NOT occur