reversibility

exothermic reaction

energy given out

endothermic reaction

energy taken in

anhydrous salts

are those that have lost their water of crystallisation, usually by heating, the salt becomes dehydrated

equilibrium

when the rate of the forward reaction equals the rate of the reverse reaction, the overall reaction is in this state

characteristics of a state in equilibrium

the concentration of reactants and products remains constant

only occurs in a closed system

closed system (chemistry)

the two reactions are interlinked and no gases can escape

le chateliers principle

the relative amounts of all the reactants and products at equilibrium depend of the conditions of the reactions, this balance is known as this

the principle states that when a change is made to the conditions of a system at equilibrium, the systems automatically moves to oppose change

what is le chateliers principles predicted changed

temperature

pressure

concentration

how does concentration effect equilibrium

increases: the equilibrium will shift to the right, this is to reduce the effect of increasing the concenctration of a reactant, this makes more product

decreases: the equilibirum will shift to the left, this is to reduce the effect of decreasing the concentration of a reactant, this makes less product

how does temperature effect equilibrium

increases: the equilibrium will shift in the dicrection of the endothermic reaction

decreases: the equilibrium will shift in the direction of the exothermic reaction

how does pressure effect equilibrium

in gaseous equations: an increase will favour the reaction that produces the least amount of molecules, a decrease will favour the reaction that produces the greatest amount of molecules

if there are the same number of moles of gases on either side of the equation there is no effect on equilibrium when pressure is changed