Question

consider the following two chemical changes:
1 when a material made of iron rusts,it mass increase.
2 when a match stick burns,its mass decrease

Answer 1

1A) The mass of iron increases as rusting happens when oxygen combines with iron therefore the mass increases.

2A) Burning and other changes in matter do not destroy matter. The mass of matter is always the same before and after the changes occur. The law of conservation of mass states that matter cannot be created or destroyed.