(English Medium) ICSE Class 9 - CISCE Question Bank Solutions for Chemistry

Give balanced equation for the following conversion [one or two steps].

A molecule of ozone to two molecules of oxygen gas.

Give balanced equation for the following conversion [one or two steps].

Oxygen to ozone gas by photolysis.

Give reason for the following:

The formation of ozone involves a chemical reaction called photolysis.

Give reason for the following:

Destruction of ozone layer is harmful for both humans and plants.

Name or state the following:

An atmospheric pollutant responsible for both global warming and ozone depletion.

Name or state the following:

The atom which reacts with oxygen to form ozone.

State in brief the drawbacks of Rutherford's atomic model correlating them with the postulates of Bohr’s atomic model.

What do the following symbol stand for?

2H₂ 

What is a chemical equation? Why it is necessary to balance it?

State the information conveyed by the following equation:

Zn_(s) + 2HCl_(aq) → ZnCl2_(aq)  + H2 ↑

What is the limitation of the reaction given in question 2?

Write the chemical equation for the following word equation and balance them.

Carbon   + Oxygen → Carbon dioxide

Write the chemical equation for the following word equation and balance them.

Nitrogen + Oxygen → Nitrogen monoxide

Write the chemical equation for the following word equation and balance them.

Calcium + Nitrogen → Calcium nitride

Write the chemical equation for the following word equation and balance them.

Calcium oxide + Carbon dioxide → Calcium carbonate

Write the chemical equation for the following word equation and balance them.

Magnesium + Sulphuric acid → Magnesium sulphate + Hydrogen

Write the chemical equation for the following word equation and balance them.

Sodium reacts with water to form sodium hydroxide and hydrogen

Balance the following equation:

 Fe + H₂O → Fe₃O₄ + H₂

Balance the following equation:

Ca + N₂ → Ca₃N₂

Balance the following equation:

Zn + KOH → K₂ZnO₂ + H₂