Question

Calculate the amount of Mercury(Hg) obtained by the decomposition of 2.16 Kg of Mercuric oxide.

Answer 1

• The chemical equation for the decomposition of mercuric oxide (HgO)

HgO $\stackrel{∆}{\to }$ Hg + ½ O₂

The molecular weight of Mercuric oxide HgO = 216g

The atomic weight of Hg (Mercury) = 200g

The atomic weight of oxygen (O) =16g

To find the amount of mercury(Hg) obtained by the decomposition of 2.16 Kg of mercuric oxide,

Convert the given mass of mercuric oxide HgO into moles

i.e., 216 g of mercuric oxide HgO =1 mole

Then 2.16Kg = 2.16 × 1000= 2.16 × 10³ g of mercuric oxide HgO =$\frac{1}{216}$× 2.16 × 10³ =10 mole

• Using the mole ratio from the chemical reaction, the moles of Hg produced in the reaction

1 mole of mercuric oxide HgO produces = 1 mole of Hg

Therefore 10 mole of Mercuric oxide HgO will produce =1×10 moles of Hg(mercury) =10 moles.

• Convert the moles of mercury Hg calculated that are produced in the decomposition reaction:

Molar mass of of mercury(Hg) = 200g

i.e., Weight of 1 mole of Mercury(Hg) =200g

Therefore weight of 10 mole of mercury(Hg) =200 × 10= 2000g =2Kg

Therefore the amount of mercury obtained by the decomposition of 2.16 Kg of mercuric oxide is equal to 2Kg.