When the reddish-brown mercury(ii) oxide (hgo) is heated, it decomposes to its elements, liquid mercury metal and oxygen gas. if 3.98 g hgo is decomposed to hg, calculate the mass of the pure hg metal produced.

Mass of mercury is 798.35 g.

Explanation:

Balanced chemical equation.

2HgO(s)   →  2Hg(l) + O₂(g)

Given data:

Mass of mercury oxide = 3.98 g

Mass of pure mercury = ?

solution:

First of all we will calculate the moles of mercury oxide.

Number of moles = mass / molar mass

Number of moles = 3.98 g/ 216.59 g/mol

Number of moles = 0.0184 mol

Now we will compare the moles of mercury and mercury oxide from balanced chemical equation.

                       HgO   :    Hg

                         2       :      2

                       3.98   :    3.98

Mass of mercury:

Mass =  number of moles × molar mass

Mass = 3.98 mol × 200.59 g/mol

Mass = 798.35 g