A 6.807g sample of an unknown compound, composed only of carbon, hydrogen, and nitrogen, produced 13.3g of CO2 and 9.52g of H2O in a combustion analysis. What is the mass percent composition of nitrogen of the unknown compound?

The mass percent composition of nitrogen of the unknown compound is, 31.1 %

Explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and nitrogen respectively.

We are given:

Mass of

Mass of

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 13.3 g of carbon dioxide, of carbon will be contained.

For calculating the mass of hydrogen:

In 18 g of water, 2 g of hydrogen is contained.

So, in 9.52 g of water, of hydrogen will be contained.

For calculating the mass of nitrogen:

Mass of nitrogen in the compound = (6.807) - (3.63 + 1.06) = 2.117 g

To calculate the percentage composition of nitrogen in sample, we use the equation:

Putting values in above equation, we get:

Hence, the mass percent composition of nitrogen of the unknown compound is, 31.1 %