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)