Question

Chapter 6: Physical and Chemical Change
1. Fill in the blanks :
1. Changes that lead to the formation of new substances are called
a
2. Melting of candle wax is a
change but its burning is
change.
3. Growth of a plant is a
change while formation of
clouds is a
change
4. A brown layer formed when an iron article is left exposed in air in an
open area is called
5. Large crystals of pure substance are obtained by
6. The brown layer deposited on an iron nail dipped in copper sulphate
solution is due to

Answer 1

Here are the required answers for your questions:

• Changes that lead to the formation of new substances are called  as chemical changes.
• Melting of candle wax is a physical change but its burning is chemical change.
• Growth of a plant is a chemical change while formation of  clouds is a physical change.
• A brown layer formed when an iron article is left exposed in air in an  open area is called rust.
• Large crystals of pure substance are obtained by crystallisation.
• The brown layer deposited on an iron nail dipped in copper sulphate  solution is due to displacement reaction.

Answer 2

• chemical synthesis

• physical change

• chemical change

• rusting of iron

• crystalization

• displacement reaction