| what is meant by a reaction being at equilibrium | when the rate of the forward and reverse reaction are equal and the concentration of reactants and products remain constant (but rarely equal) |
| what is meant by dynamic equilibrium | when rates of forward and reverse reaction are equal |
| what is meant by a closed system | when the reaction is carried out in a sealed container so no reactants or products are lost |
| in what sort of system only can equilibrium occur | closed system |
| why do chemists move the position of equilibrium | to favour the products and maximised their profits
eg. the haber process uses high pressure to favour the products and a medium temperature |
| what is meant by 'position of equilibrium lies to the left' | concentration of the reactants is greater than the products at equilibrium |
| what is meant by 'position of equilibrium lies to the right' | concentration of the products is greater than the concentration of the reactants |
| what does le Chateliers principle state | any change made to a reaction which is at equilibrium will result in the equilibrium position moving to minimise the change made
(put simply, if there is a change in reaction that increases the concentration of either products or reactants, the system will try to reverse that change) |
| what is the effect of changing temperature on position of equilibrium | increasing the temperature favours the endothermic reaction - the position of the equilibrium shifts in the direction of the endothermic reaction
decreasing temperature favours the exothermic reaction - the position of equilibrium shifts in the direction of the exothermic reaction |
| what is the effect of changing pressure on the position of equilibrium | changing pressure only affects substances in a GASEOUS STATE
increasing pressure favours the side with the lower gas volume (less moles of gas)
decreasing the pressure favours the side with the higher gas volume (more moles of gas) |
| what effect does changing concentration have on position of equilibrium | adding a reactant or removing a product will shift equilibrium to the right (to compensate the gain/loss)
adding a product or removing a reactant will shift equilibrium to the left
hydroxide and hydrogen ions will react to form water, which will add a product or reactant depending on the reaction |
| what effect do catalysts have on equilibrium | they have no effect on equilibrium position, they will allow equilibrium to be reached quicker and at a lower temperature |
