Physical changes are always irreversible.

Important Questions on Physical and Chemical Changes

EASY

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q 5

In case of chemical changes, a new product is formed.

HARD

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q 6

Copper sulphate (blue) changes to iron sulphate (reddish brown) when an iron nail is dropped in it.

EASY

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q 7

The presence of a precipitate in a reaction is shown by a downwards arrow.

MEDIUM

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q 8

A change or a reaction in which heat is absorbed or taken in from the surroundings is called an exothermic reaction.

MEDIUM

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q 9

The process of rusting requires both oxygen and moisture (water).

MEDIUM

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q 10

Small crystals are formed during slow cooling in the process of crystallisation.

EASY

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q I

Define elements.

MEDIUM

7th CBSE

IMPORTANT

Sciwise - A coursebook of Science>Chapter 7 - Physical and Chemical Changes>EXERCISE>Q I

Define atoms.