Subject Experts Solutions for Exercise 2: PRACTICE QUESTIONS (COMPETITION WING)

The number of atoms in one molecule of oxygen is _____.

Three atoms of chlorine are represented as _____.

Burning of cracker is a _____ and _____ change.

Identify the incorrect formulae among the following: $\left(\mathrm{A}\right) {\mathrm{CaO}}_2, \left(\mathrm{B}\right) {\mathrm{Na}}_2\mathrm{O}, \left(\mathrm{C}\right) {\mathrm{Mg}}_3{\mathrm{S}}_2, \left(\mathrm{D}\right) {\mathrm{Mg}}_2\mathrm{O}, \left(\mathrm{E}\right) \mathrm{CaS}$. 

Match the following:

What type of change is in the formation of coal?

Molecules of some elements and compounds are given below. Identify hydrogen, hydrogen chloride, water, carbon dioxide, carbon disulphide, carbon tetrachloride.

Complete the following table: