10.1 Reaction Rates

How fast a reactant is being used up or how fast a product is being formed

Change in concentration of a reactant or a product in a given time

Change in concentration/time Units - moldm^-3s^-1

At the start of the reaction, as each reactant is at its highest concentration

Reactants are being used up and concentrations decrease

Concentration (aq) Pressure (g) Temperature Use of catalyst Surface area (s)

2 reacting particles must collide for a reaction to occur

Particles collide with the correct orientation Particles have sufficient energy to overcome activation energy barrier of the reaction

Increasing temperature = increasing rate of reaction Particles have greater kinetic energy, move around more Greater frequency of collisions, greater frequency of successful collisions Also, greater proportion of particles have activation energy

Increasing concentration = increasing rate of reaction Particles become more crowded Greater frequency of collisions, more successful collisions

Catalysts increase the rate of reaction Provide alternative reaction pathway with lower activation energy Greater proportion of particles have activation energy Rate of successful collisions increases compared to rate in an uncatalysed reaction

More surface area = increased rate of reaction More reactant particles are available for collisions Collisions are more likely so particles collide more often

Monitor removal of a reactant Measure formation of product

Monitoring gas produced using a gas syringe - check at regular intervals Using an upturned measuring cylinder in water

Monitor volume of gas produced at regular time intervals Monitor loss of mass of reactants using a balance