Question

Classify the following changes as physical or chemical changes. a. Water boils. b. Salt dissolves in water c. Milk turns sour d. A metal rusts.

Answer 1

Answer:

Water boils - physical change

Salt dissolves in water- chemical change

Milk turns sour- chemical change

metal rusts - chemical change

Explanation:

A chemical change refers to changes that are irreversible and the process involves the evolution of heat along with the formation of a new substance, examples include;Salt dissolves in water, Milk turns sour, metal rusts etc

The boiling of water is a physical change. The water can be cooled and the vapour condensed,hence, the boiling of water is a physical change.

Physical changes are easily reversible and no new substance is formed.