EASY
7th CBSE
IMPORTANT
Earn 100

Discuss an example of physical and chemical changes happening together.

Important Questions on Changes and Reactions

MEDIUM
7th CBSE
IMPORTANT
Giving one example of each kind, show that a change in energy takes place when a physical or a chemical change occurs.
MEDIUM
7th CBSE
IMPORTANT
Describe an activity to find the conditions required for rusting.
MEDIUM
7th CBSE
IMPORTANT
Which of the following is not a reversible change?
EASY
7th CBSE
IMPORTANT
Which of the following is a reversible change?
EASY
7th CBSE
IMPORTANT
During which of the following changes are new substances formed?
EASY
7th CBSE
IMPORTANT
Rusting takes place in _____.
EASY
7th CBSE
IMPORTANT
In which of the following process is light absorbed?
MEDIUM
7th CBSE
IMPORTANT
Match the columns A and B.
  A   B
(a) Neutralization reaction (i) Burning of carbon
(b) Displacement reaction (ii) Formation of carbon dioxide when baking soda is heated
(c) Decomposition reaction (iii) Deposition of copper when an iron nail is placed in a solution of copper (II) sulphate
(d) Combination reaction (iv) Formation of sodium chloride and water when hydrochloric acid reacts with sodium hydroxide.