Polypropylene is a plastic formed by polymerizing propylene, which has the empirical formula CH₂. If a sample of propylene with a mass of 21.0 grams occupies a volume of 11.2 L at STP (0 °C and 1 atm), what is the molecular formula of this gas?

Question

Quizplus · Accepted Answer

At STP, 1 mole of gas occupies 22.4 L. Since 11.2 L is half of 22.4 L, the sample contains 0.5 moles. The molar mass of the sample is 21.0 g / 0.5 mol = 42 g/mol, which corresponds to the molecular formula C₃H₆.

Polypropylene Is a Plastic Formed by Polymerizing Propylene, Which Has