Copy and write in the missing symbols or formulae of the following symbol equation:

Carbon $+$ Oxygen $\to$ Carbon dioxide

 _____   $+$  _____  $\to$ ${\mathrm{CO}}_2$

Copy and write in the missing symbols or formulae of the following symbol equation:

Zinc $+$ Chlorine $\to$ Zinc chloride

_____ $+$ _____ $\to$ ${\mathrm{ZnCl}}_2$

Copy and write in the missing symbols or formulae of the following symbol equation:

Calcium $+$ Sulphuric acid $\to$ Calcium sulphate $+$ Hydrogen

 _____   $+$ ${\mathrm{H}}_2{\mathrm{SO}}_4$    $\to$ ${\mathrm{CaSO}}_4$ $+$ _____.