Question

Complete and balance the following equations:

$\mathrm{HgO}\stackrel{\mathrm{Heat}}{\to }\mathrm{\_\_\_\_\_}+{\mathrm{O}}_2$

Answer 1

When heat is applied to mercuric oxide it decomposes into mercury and oxygen.

$\underset{\mathrm{Mercuric}\mathrm{oxide}}{\mathrm{HgO}\left(\mathrm{s}\right)}\to \underset{\mathrm{Mercury}}{\mathrm{Hg}\left(\mathrm{l}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

Balancing-

• To get 2 oxygen atoms on the reactant side, we multiply HgO by 2.
• Now we get 2 Hg atoms on the reactant side, we multiply Hg on the product side by 2.
• Now, the equation is balanced.
• Hence, the balanced equation is-

$\underset{\mathrm{Mercuric}\mathrm{oxide}}{2\mathrm{HgO}\left(\mathrm{s}\right)}\to \underset{\mathrm{Mercury}}{2\mathrm{Hg}\left(\mathrm{l}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}$

• This is an example of a decomposition reaction.
• A decomposition reaction can be defined as a chemical reaction in which one reactant breaks down into two or more products.