Question

A 2.95 g sample of an unknown chlorofluorocarbon is decomposed and produces 579 mL of chlorine gas at a pressure of 756 Torr and a temperature of 298 K. Part A What is the percent chlorine (by mass) in the unknown chlorofluorocarbon?

Answer 1

Ans. #Step 1: Calculate the moles of chlorine gas (Cl₂) using ideal gas equation –

Now, mass of chlorine gas produced = moles x MW = 0.0235 mol x 70.9054 g mol^-1

                                                                        = 1.667 g

# Step 2: % Cl₂ (wt / wt) = (Mass of Cl₂ / Mass of sample) x 100

                                                = (1.667 g / 2.95 g) x 100

                                                = 56.51 %