Question

What mass will 33.6 L of chlorine gas (Cl2) have at STP?

Responses

35 g

35 g

53 g

53 g

71 g
71 g

106 g

Answer 1

At STP 1 mol gas = 22.4 L, so moles = 33.6 L / 22.4 L·mol⁻¹ = 1.50 mol. Molar mass Cl2 = 2×35.45 = 70.90 g·mol⁻¹. Mass = 1.50 mol × 70.90 g·mol⁻¹ = 106 g.