Question

A 0.00215g sample of polystyrene, a polymer composed of carbon and hydrogen, produced 0.00726g of CO₂ 0.00148g of H₂O in combustion analysis. What is the empirical formula for polystyrene?

Short answer

- CH is the empirical formula for polystyrene.

Step-by-step solution

Calculating number of carbon moles

To calculate this we use the produced mass from the question

Moles= 0.00726g/44g= 1.65 x 10^-4 mol CO2

So moles of carbon will also be 1.65 x 10^-4 mol

Calculating moles of water 

Moles=0.00148g/18g= 8.22 x 10^-5 mol H2O

In water, the mo les of “H” are double the moles of water

So moles of H = 1.64 x 10^-4 mol

The number of moles of C and H is the same so, the empirical formula is CH.