Kinetics

Rates of reaction

Rate = change in concentration divided by time

Usually:

• The rate is fastest at the start of the reaction since each reactant has its greatest concentration
• Rate slows as the reaction progresses as the concentration of the reactants decreases
• Rate becomes zero when the reaction stops (normally when one of the reactants have been used up)

The rate of reaction can be affected by different factors 

• Temperature - increases the amount of kinetic energy which results in more successful collisions. At higher temperatures the peak moves to the right (higher energy) with a lower height.

• Pressure of gases - the particles are closer together so are more likely to react
• Concentration of solutions - there are more particles that are closer together so collide more frequently
• Catalysts - lowers the activation energy needed and so provides an alternative route.
• Surface area - small pieces have many surfaces for reacting particles to collide with

Measuring the rate of reaction

• Change in gas volume - volume of gas can be recorded by using a gas syringe at various times
• Change in gas pressure - change in gas pressure can be measured by using a manometer
• Change in mass - if a…