Question

how is the mixing of iron and sulphur a physical? why does it become a chemical change on heating? explain giving reason.​

Answer 1

Explanation:

Physical change:

• The properties of iron and sulphur do not change when they are separated.
• There is no formation of a new product in this change.
• There is no change in the heat energy level of the mixture.
• The change is temporary and reversible as iron and sulphur can be mixed again.

Chemical Change:

• There are changes in properties of both on heating, they lose their magnetic power.
• A new substance, iron sulphide is formed.
• The heat energy is released when the iron and sulphur mixture is heated. The test tube becomes red hot.
• The change is permanent, which means it cannot be reversed.