Rates of Reaction

                The rate of a chemical reaction is a measure of how fast the reaction takes place. A rapid reaction will be completed in a short period of time. Other reactions are very slow, like the rusting of iron for instance. However, multiple factors can alter the rate of reaction.

            The more concentrated the reactants are, the greater the rate of reaction will be. This is because increasing the concentration of the reactants increases the number of collisions between particles and, therefore, increases the rate of reaction. This also explains why the fastest rate of reaction is usually as soon as the reactants are mixed, i.e. they are both at their highest concentrations. As the reaction dies out, the concentrations of the substances decreases.

            Furthermore, an increase in temperature also produces an increase in the rate of reaction. When a mixture of reactants is heated, the particles move faster. Since the particles are moving faster, they will travel a greater distance in a given time and so will be involved in more collisions and so the rate of reaction increases.

            Additionally, the surface area of a particle has an effect on the rate of reaction as well. When one of the reactants is a solid, the reaction takes place on its surface. By breaking up the solid into smaller pieces, the surface area is increased, giving a greater area for collisions to take place and so causing an increase in the rate of reaction.

Another way to hasten up reactions is to use a catalyst. A catalyst is a substance which can alter the speed of a reaction, but remains chemically unchanged at the end of the reaction. Catalysts usually speed up reactions. Those that slow reactions down are called inhibitors. Catalysts speed up reactions by providing an alternative pathway for the reaction, one that takes less energy. More collisions will, therefore, have enough energy for this new pathway.

            Two last factors that effect the rate of reaction are pressure and light. When one or more of the reactants are gases, an increase of pressure can cause a greater rate of reaction. This is because the increase in pressure forces the particles closer together, causing more collisions. Light, furthermore, can also increase the rates of some reactions. In fact, light has a similar effect to an increase in temperature.

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