Changes around us

Which one of the steps while burning a candle is not reversible?

• Melting of solid wax

• Liquid wax changes into vapours

• Wax vapour burns into flame

• All of these

Which is the way to make a change happen?

• Heating a substance

• Cooling a substance

• Mixing a substance with another substance

• All of these

Rusting of iron is an example of

• Slow change

• Fast change

• Reversible change

• Physical change0

Which of the following is a chemical change?

• Evaporation of water

• Burning of fuels

• Moving of a wheel

• Breaking of a brick

Changes that lead to the formation of new substance are called

• Physical changes

• Reversible changes

• Chemical changes

• All of these

Heat is a form of

• Change

• Energy

• Work

• All of these

Conversion of a solid to liquid by heating is called fusion

• True

• False

If the removal of the cause of change leads to regain the original situation, then the change is known as

• Irreversible

• Permanent

• Slow

• Reversible