(a) Give one example of a chemical reaction. (b) State two characteristics of the chemical reaction which takes place when dilute sulphuric acid is poured over zinc granules. (c) Give two characteristics of the chemical reaction which occurs on adding potassium iodide solution to lead nitrate solution.

• A chemical reaction results in new substances by undergoing certain reactions and

There will be reactants on the left hand side and products on the right hand side. An example for chemical reaction is

An example of combustion is methane + oxygen forms carbon dioxide and water. This can be written as a balanced symbol equation:

CH4 + 2O2 →CO2 + 2H2O

• When dilute sulphuric acid is poured over zinc granules heat will liberate thus the reaction becomes exothermic

Hydrogen gas is evolved which burns with a sound

• 2KI (aq) + Pb(NO ) (aq) → PbI (↓) + 2 KNO (aq)

When solutions of lead nitrate and potassium iodide are mixed together a yellow precipitate of lead iodide is formed. This is an example for Double Displacement Reaction.