If one of the reactants is a solid, the surface area of the solid will affect how fast the reaction goes. This is because the two types of molecule can only bump into each other at the liquid solid interface, i. So the larger the surface area of the solid, the faster the reaction will be. Smaller particles have a bigger surface area than larger particle for the same mass of solid.
There is a simple way to visualize this. Take a loaf of bread and cut it into slices. Each time you cut a new slice, you get an extra surface onto which you can spread butter and jam. The thinner you cut the slices, the more slices you get and so the more butter and jam you can put on them.
This is "Bread and Butter Theory". You should have come across the idea in your biology lessons. By chewing your food you increase the surface area so that digestion can go faster. What affect does pressure have on the reaction between two gasses? You should already know that the atoms or molecules in a gas are very spread out. For the two chemicals to react, there must be collisions between their molecules.
By increasing the pressure, you squeeze the molecules together so you will increase the frequency of collisions between them. This is collision theory again. In a diesel engine, compressing the gaseous mixture of air and diesel also increases the temperature enough to produce combustion. This is done by cutting the substance into small pieces, or by grinding it into a powder.
If the surface area of a reactant is increased:. Compared to a reaction with lumps of reactant, the graph line for the same reaction but with powdered reactant:. Chemistry Chemical Kinetics Rate of Reactions. Simon Moore. Jan 30, Explanation: Rates of reaction increase according to the frequency of collisions between the reacting species. Related questions How do you calculate rate of reaction? How can rate of reaction be affected?
How can rate of reaction be increased? How can temperature affect reaction rate? How can the rate of reaction be calculated from a graph?
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