Question

Find the missing words in the given sentences and rewrite the sentences again:
1. A physical change is not accompanied by evolution or absorption of heat.
2. Changes which occur periodically at a interval of time are called periodic change.

Answer 1

Answer:

A chemical change is generally associated with evolution and absorption of heat.

Periodic and non-periodic changes Changes that repeat at regular intervals are called periodic changes. Examples: The occurrence of day and night and the waxing and waning of the moon. Certain changes that do not repeat themselves at regular intervals of time, and such changes are called non-periodic changes.