Unit 2 - Equilibria

Question 1

Equilibrium

Answer 1

Reversible reaction reach a dynamic equilibrium in a closed system.

The rates of the forward and reverse reactions are equal at equilibrium.

The concentrations of reactants and products remain constant at equilibrium, but are rarely equal.

Question 2

Equilibrium Position

Answer 2

If the equilibrium mixture contains a greater proportion of products than reactants then the position of equilibrium lies to the right.

If the equilibrium mixture contains a greater proportion of reactants than products then the position of equilibrium lies to the left.

Question 3

Changing the Concentration

Answer 3

Adding reactant (or removing product) speeds up the forward reaction, so equilibrium shifts to the right to produce more product.

Adding product (or removing reactant) speeds up the reverse reaction, so equilibrium shifts to the left and more reactant will form.

Question 4

Changing the Pressure

Answer 4

Increasing the pressures shift equilibrium in the direction with lower no. of moles of gaseous molecules.

Decreasing the pressure shifts equilibrium to the side with higher no. of moles of gas.

If the no. of moles of gas is equal for products and reactants, changing the pressure has no effect

Question 5

Changing the Temperature

Answer 5

Increasing temperatures shifts equilibrium in the endothermic direction.

Decreasing temperature shifts equilibrium in the exothermic direction.

Question 6

Catalysts

Answer 6

A catalyst speeds up the forward and reverse reactions so equilibrium is reach more quickly. A catlyst has no effect on the position of equilibrium.