Controlling the Rate

Collision Theory
1. Reactant molecules must collide with enough energy for chemical reaction to occur
2. Activation energy (Ea) - minimum kinetic energy required for reaction to occur
3. Activated Complex - Intermediate stage, high energy, unstable arrangement of atoms
4. Energy given out when new bonds form as atoms rearranged into product molecules
Reaction Rates
1. average rate = change in quantity/change in time
2. relative rate = 1/t
Altering Factors
1. Temperature
  1. Temp increase, then particles have more kinetic energy and so an increased chance of possible collisions
2. concentration
  1. Conc increase, then more particles, so more collisions so increase in rate of reaction
3. Particle size
  1. Particle size decrease, then larger surface area, increased chance of collisions, faster rate
4. Use of Catalyst
  1. Lowers Activation Energy, provides alternative route, provides surface for reaction to occur on
  2. Homogenous - same state Heterogenous - different state

Resource summary

	Created by Emma.h.watt about 10 years ago