RATE OF REACTION

concentration of reactants

pressure (affects gas only)

surface area (particle size)

temperature

catalysts

enzymes

-for a more concentrated solution, more particles are present per unit volume

at high pressure, particles are closer to one another

-no. of collisions increases

-no. of effective collisions increases

frequency of collisions increases

no. of effective collisions increase, increasing rate of reaction

smaller particle size increases the total surface area of the solid

frequency of collisions increases

no. of effective collisions increases, increasing rate of reaction

increasing temp. would increase average KE of the particles

more particles possess energy equal to or greater than the activation energy

particles move faster

frequency of collisions increase

no. of effective collisions increase, increasing rate of reaction

activation energy

is the minimum amount of energy that reactant particles must possess in order for a chemical reaction to occur

catalysts are substances which increase the speed of a chemical reaction and remains chemically unchanged at the end of the reaction

increase speed of reaction by providing an alternative pathway for the reaction to proceed

a catalysed reaction has lower activation energy than the reaction without the catalyst

eg. transition metals

biological catalysts found in animals and plants

proteins

specific in action (certain enzymes only break down certain things)

sensitive to temperature changes (will denature when temp. is too high/low)

sensitive to pH changes (will denature when pH too high/low)