General Chemistry 1

Question

A 9.75 L container holds a mixture of two gases, gas A and gas B, at 25 degrees celcius. The partial pressures of gas A and gas B are 0.419 bar and 0.511 bar, respectively. A 0.130 mol sample of a third gas, gas C, is added with no change in volume or temperature. Calculate the total pressure of the system.

Answer:

Total pressure of the system: _______ bar

Answer 1

Usually, we deal with atmospheres as pressure and R gas constant has a value of 0.0821 Latm/Kmol.

Since this question gives pressure in units of bar, we will use R = 0.08314 Lbar/Kmol.

Find the partial pressure of gas C:

PV = nRT

P = nRT/V = (0.130 mol)(0.08314 Lbar/Kmol)(298K) / 9.75 L = 0.330 bar

Total pressure = sum of partial pressures = 0.419 bar + 0.511 bar + 0.330 bar = 1.26 bar