CHAPTER 4 - STOICHIOMETRY: QUANTITATIVE INFORMATION ABOUT CHEMICAL REACTIONS

Question

Styrene, the building block of polystyrene, consists of only C and H. If 0.397 g of styrene is burned in oxygen and produces 1.342 g of CO₂ and 0.275 g of H₂O what is the empirical formula of styrene?

Empirical formula:  

Answer 1

Find moles of C and moles of H. That will give you the empirical formula.

1.342 g CO2 x 1 mole CO2/44 g x 1 mole C/mole CO2 = 0.0305 moles C

0.275 g H2O x 1 mole H2O/18 g x 2 mole H/mole H2O = 0.0305 moles H

Since mole ratio of C:H is 1:1, the empirical formula is CH