To use partial pressure in gas law calculations. In a mixture of gases, the tota

Question

To use partial pressure in gas law calculations. In a mixture of gases, the total pressure of the gas mixture is equal to the sum of the partial pressures of the individual gases. For example if you have a mixture of helium, at 2 atm and argon at 4 atm, then the total pressure of the gas inside the cylinder is 6 atm. (Figure 1) Similarly, if you know the total pressure of a gas mixture, you can use the number of moles to find the partial pressure, or the partial pressures to find the number of moles. Example Problem: A mixture of N_2, O_2, and He gases a mixture of He, ar, and Xe has a total pressure of 2.60 atm. The partial pressure of He is 0.300 atm, and the partial pressure of are is 0.350 atm. What is the partial pressure of Xe? A volume of 18.0 L contains a mixture of 0.250 mole N_2, 0.250 moles O_2, and an unknown quantity of He. The temperature of the mixture is 0 degree C, and the total pressure is 1.00 atm. How many grams of helium are present in the gas mixture?

Explanation / Answer

Given

Volume = 18 L

Temperature = 0 C = 273 K

Pressure = 1 atm

R = 0.08206 L.atm/mol.K

P * V = n * R * T

1 atm * 18 L = n * 0.08206 L.atm/mol.K * 273 K

n = 0.8035 moles this is total no. of moles of present

Given

No. of moles of N2 = 0.250

No. of moles of O2 = 0.250

No. of moles of He = total No. of moles - ( No. of moles of N2 + No. of moles of O2) = 0.8035 - (0.25 + 0.25)

No. of moles of He = 0.3035 moles of He

Mol. wt of He = 4 g/mol

Mass of He = No. of moles * Mol. wt = 0.3035 moles * 4 g/mol = 1.214 g Answer

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.