# How many grams of calcium oxide are needed to produce 36.0 g of Hg? 4HgS +4CaO \longrightarrow...

## Question:

How many grams of calcium oxide are needed to produce 36.0 g of Hg? {eq}4HgS +4CaO \longrightarrow 4Hg +3CaS + CaSO_4. {/eq}

## Moles of the substance:

Mole is considered as one of the seven basic units in the international system(SI). it is used to express the amount of the substances. It is defined as the ratio of the mass of the compound to the Molar mass of the compound.

In the given reaction calcium oxide reacts with mercury sulfide to produce mercury and calcium sulfide, and calcium sulfate

Given,

• Mass of Hg = 36 g
• Molar mass of Hg = 201 g/mol
• Molar mass of CaO = 56 g/mol

The balanced chemical reaction is:

{eq}4HgS +4CaO \longrightarrow 4Hg(l ) +3CaS + CaSO_4. {/eq}

According to the balanced chemical reaction,

4 mol calcium oxide gives 4 mol Hg

Or,

224 g calcium oxide gives 804 g mercury

So, Mass of CaO needed = {eq}\dfrac{224\times36}{804}=10.02\,g {/eq}