If a sample of ammonia gas,NH₃,reacts with oxygen and platinum catalyst to give 55.5 L of nitrogen monoxide gas at STP,what mass of ammonia reacted? NH₃(g)+ O₂(g) NO(g)+ H₂O(g)

Question

If a sample of ammonia gas,NH₃,reacts with oxygen and platinum catalyst to give 55.5 L of nitrogen monoxide gas at STP,what mass of ammonia reacted? NH₃(g)+ O₂(g)  NO(g)+ H₂O(g)

Quizplus · Accepted Answer

Using the balanced equation, we can see that the molar ratio between NH₃ and NO is 1:1. Therefore, the number of moles of NH₃ that reacted is equal to the number of moles of NO produced. From the ideal gas law, we know that n = PV/RT, where n is the number of moles, P is the pressure, V is the volume, R is the gas constant, and T is the temperature. At STP, we have P = 1 atm and T = 273 K. Therefore, we can calculate the number of moles of NO produced as follows:

n(NO) = PV/RT = (1 atm)(55.5 L)/(0.0821 L·atm/mol·K)(273 K) = 2.20 mol

Since the molar ratio between NH₃ and NO is 1:1, we know that 2.20 mol of NH₃ also reacted. The molar mass of NH₃ is 17.03 g/mol, so the mass of NH₃ that reacted is:

m(NH₃) = n(NH₃)·M(NH₃) = (2.20 mol)(17.03 g/mol) = 37.5 g

Therefore, the best choice is B, 42.2 g (the closest choice to the calculated mass).

If a Sample of Ammonia Gas,NH₃,reacts with Oxygen and Platinum