The chemical formula of sulphuric acid is ${\mathrm{H}}_2{\mathrm{SO}}_4$.  Altogether, how many atoms are present? What if it is $2{\mathrm{H}}_2{\mathrm{SO}}_4$? Determine the total number of atoms present in the molecules given below:

${\mathrm{CO}}_2$

$2{\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}$

$5{\mathrm{H}}_2\mathrm{O}$ 

$3\mathrm{NaCI}$

$7{\mathrm{NH}}_3$

${\mathrm{ZnCl}}_2$

Zinc $+$ Hydrochloric acid $\to$ Zinc chloride $+$ Hydrogen gas $\uparrow$

The reaction between zinc and hydrochloric acid can be represented as follows:

$\mathrm{Zn}+\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2$

$\mathrm{Zn}+\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2$

Rewrite the equation as follows:

$\mathrm{Zn}+2\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2$

Examine the number of atoms in the equation.

Now, look at the balanced chemical equations given below. Write down the reactants and products in the table:

(1) $\mathrm{C}+{\mathrm{O}}_2\to {\mathrm{CO}}_2$

(2) ${\mathrm{H}}_2+{\mathrm{Cl}}_2\to 2\mathrm{HCl}$

(3) $2{\mathrm{H}}_2+{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}$

$\mathrm{Mg}+{\mathrm{O}}_2\to \mathrm{MgO}$

$\mathrm{NaOH}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{O}$

${\mathrm{N}}_2+{\mathrm{H}}_2\to {\mathrm{NH}}_3$

${\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$

Classify the following into elements and compounds.

Ammonia, sugar, nitrogen, mercury, sodium chloride, water, copper sulphate, sodium, carbon.