Automotive airbags inflate when a sample of NaN ₃ (molar mass = 65 g/mol) is rapidly decomposed. What mass of NaN ₃ is required to produce 368 L of nitrogen gas (molar mass = 28 g/mol) with a density of 1.25 g/L?

2 NaN₃(s) → 2 Na(s) + 3 N₂(g)

Question

Quizplus · Accepted Answer

Use the ideal gas law to find the number of moles of nitrogen gas produced: n = PV/RT = (1.25 g/L)(368 L)/(0.0821 L·atm/mol·K)(298 K) = 18.5 mol According to the balanced chemical equation, each mole of NaN ₃ produces 3 mol of nitrogen gas. Therefore, the number of moles of sodium azide needed is: n(NaN ₃) = n(N2)/3 = 6.17 mol The mass of NaN ₃ needed is: m = n(MW) = (6.17 mol)(65 g/mol) = 400.2 g Therefore, the best choice is B, 712 g.

Automotive Airbags Inflate When a Sample of NaN 3

Automotive Airbags Inflate When a Sample of NaN ₃