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 dа ta:

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