EVERYDAY SCIENCE

Detailed explanation-1: -The burning of wood is a chemical change as it leads to the formation of new substances like Carbon dioxide gas, water vapour, ash, etc. There are some substances that do not undergo complete combustion or do not react at all, these substances form the fire ash.

Detailed explanation-2: -The burning of wood leads to the formation of new substances like ash(carbon), carbon dioxide gas, water vapour, heat and light. This change is irreversible and hence a chemical change. While cutting wood into smaller pieces is a physical change as there is no change in the original composition of wood.

Detailed explanation-3: -Cutting of wood into small pieces is a irreversible physical change as no new substance is formed and there is no change in chemical composition of wood. Whereas, burning of wood is a chemical change as a new substance is formed.

Detailed explanation-4: -Burning is a chemical change. This is because, new substances (e.g. ash and carbon dioxide CO2) are formed during burning.

Detailed explanation-5: -Burning of wood and rusting of iron bar are examples of chemical changes.