Question

Give reasons why-sepration of mixtures E.g. iron from a mixture of iron & sulphur is a physical change, but heating a mixture of iron & sulphur is considered a chemical change.

Answer 1

There are several differences between a physical and chemical change in matter or substances. A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

The separation of iron from a mixture of iron and sulphur is a physical change acid can be separated by magnetic separation and no new substance is formed whereas iron and sulphur when heated together produce iron sulphide which is the new substance and it is a chemical change.