Question

nitrogen and oxygen gases are mixed in a 0.85 l container at 285 k. the total pressure exerted by the gases is 950 mm hg, and the partial pressure of nitrogen is 530 mm hg. how many moles of hydrogen gas are in the mixture? note: 760 mm hg = 1 atm. 0.045 mols 35 mols 15 mols 0.020 mols

Explanation:

Step1: Calculate the partial pressure of oxygen

According to Dalton's law of partial pressures \(P_{total}=P_{N_2}+P_{O_2}\). So \(P_{O_2}=P_{total}-P_{N_2}\).
\(P_{O_2}=(950 - 530)\text{ mm Hg}=420\text{ mm Hg}\).
Convert pressure to atm: \(P_{O_2}=\frac{420}{760}\text{ atm}\approx0.553\text{ atm}\)

Step2: Use the ideal gas law \(PV = nRT\) to find the number of moles of oxygen

The ideal gas law is \(n=\frac{PV}{RT}\), where \(R = 0.0821\text{ L}\cdot\text{atm}\cdot\text{mol}^{-1}\cdot\text{K}^{-1}\), \(V=0.85\text{ L}\), \(T = 285\text{ K}\)
\(n=\frac{0.553\times0.85}{0.0821\times285}\)

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Answer:

0.020 mols