Changes around us

Which of the following is a reversible change?

• tearing of paper

• blowing air in a balloon

• breaking of stick

• baked chapati

Pick the change that can be reversed from the following.

• Melting of ghee

• Cutting of trees

• Burning of candle

• Blooming of flower

Rolling of chapati and baking of chapati are the changes that

• can be reversed

• cannot be reversed

• can be reversed and cannot be reversed, respectively

• cannot be reversed and can be reversed, respectively

Which of the following change cannot be reversed?

• Melting of chocolate

• Freezing of ice cream

• Opening a door

• Hardening of cement

Salt can be separated from its solution (salt dissolved in water), because

• mixing of salt in water is a change that can be reversed by evaporation

• mixing of salt in water is a change that can be reversed by heating and melting salt

• mixing of salt in water is a change that cannot be reversed

• mixing of salt in water is a permanent change

When iron is heated it

• contracts

• expands

• dissolves

• evaporates

The process where water changes into a vapour after heating is called

• decantation

• filtration

• condensation

• evaporation

When water is mixed with plaster of paris it becomes

• soft

• very soft

• very hard

• hard

Boiling an egg is a

• chemical change

• physical change

Freezing water to make ice cubes is a

• physical change

• chemical change