Equilibrium

-Forward reaction: initially reactants are used up quickly but then slow as their concentration drops -Backward reaction: initially reactants are reformed slowly but then speed up as the concentration of products increases.

point at which the rate of the forward reaction equals the rate of the backward reaction. The concentration of each substance remains constant. This only occurs in a closed system.

the concentration of the products/ the concentration of the reactants -the molar values in front of each species are the powers in the Kc expression

moldm-3

all reactants and products are in the same state so all reactants and products are included in the final Kc expression.

all reactants and products are in different states so we don’t include solids and pure liquids in the final Kc expression. This is due to their concentrations remaining constant.

Initial moles Change in moles Equilibrium moles

-calculate initial moles of reactant -the initial moles of product is zero -calculate equilibrium moles of product -knowing the equilibrium moles of products, calculate the change in moles -knowing the change in moles, calculate the equilibrium mole of the other compounds. (times the reactants by minus the change in moles of products) -use equilibrium moles to calculate concentration

-substitute -rearrange -assume the different compounds hold the same concentration

sum of all the pressures of the individual gases (partial pressure)

total pressure= pressure of reactants + pressure of products -molar ratios can be used to calculate partial pressures but they must be on the same side of the reversible reaction

proportion of a. age in a gas mixture

number of moles of gas/ total number of moles of gas in the mixture

mole fraction of gas (times) total pressure in mixture

kPa

-only includes gases partial pressures of products/ partial pressures of reactants

if a reaction at equilibrium is subjected to a change in pressure, temperature or concentration, the position of equilibrium will move to counteract the change.

reactants and products are in the same state

If we increase concentration of products/ reactants, equilibrium will shift to try to reduce concentration. The opposite will happen if concentration decreased. This only happens in homogenous equilibria.

If we increase pressure, equilibrium will shift to the side with fewer number of gas particles which will reduce the pressure. The opposite will happen if pressure decreased. This only happens in homogenous equilibria.

Increasing temperature will shift equilibrium in the endothermic direction which will reduce the temperature. The opposite will happen if temperature decreased. This only happens in homogenous equilibria.

-no effects on the position of equilibria -the rate of the forward and backward reaction will be increase equally -will speed up the rate at which equilibrium is reached but have no effect on the yield

-if temperature change causes equilibrium to shift to the right, Kp will increase -if temperature change causes equilibrium to shift to the left, Kp will decrease

Both have no effect on the value of Kp and Kc