Rate of Reaction

Key Stage 4

Meaning

Rate of reaction is a measure of how quickly the reactants react to create the products.

About the Rate of Reaction

The longer the time taken for a reaction the lower the rate of reaction. The shorter the time taken for a reaction the higher the rate of reaction.

High rates of reaction are important to in industries where a lot of products are needed in a short amount of time. This can save money.

Low rates of reaction are important in materials that corrode with chemicals in the environment. This allows them to last a long time before destroyed by Oxidation or chemical weathering.

Examples

Rusting has a low rate of reaction.	Burning Magnesium ribbon has a high rate of reaction.

Determining the Rate of Reaction

There are two approaches to finding the rate of reaction for some chemicals.

• Find out how quickly the reactants are used up.
• Find out how quickly new products are made.

Continuously Measuring Volume of Gas

For reactions which give off a gas the volume of gas produced can be measured throughout an experiment to find the rate of reaction.

This diagram shows a possible setup for measuring the gas given off during an experiment.

Continuously Measuring the Mass

For reactions which give off a gas the mass of reaction mixture can be measured throughout an experiment to find the rate of reaction.

This diagram shows a possible setup for measuring the mass of the reaction mixture during an experiment.

Continuously Measuring the Opacity

For reactions in which the reactants are in a transparent solution but the products form an insoluble precipitate that is opaque then the opacity can be measured.

This diagram shows a possible setup for identifying when a mixture becomes opaque during a reaction by drawing a black cross on a white tile and observing until the cross can no longer be seen.