Amixture with h2 and he exerts a total pressure of 0.48 atm. if there is 1.0 g of h2 and 1.0 g of he in the mixture, what is the partial pressure of the helium gas?

0.161 atm

Explanation:

To calculate the partial pressure of helium (He), use the equation PHe = XHe × Ptotal, where XHe is the mole fraction of He, and Ptotal is the total pressure given in the question.

To calculate the mole fraction of helium, we must first calculate the number of moles of helium and hydrogen gas in the mixture.

nHe = 1.00g He/ 4.003 g/mol = 0.2498 mol

nH2 = 1.00g H2 / 2.016 g/mol = 0.4960 mol

ntotal= 0.2498 mol + 0.4960 mol= 0.7458 mol

We can now solve for the partial pressure of helium as follows. Recall that the mole fraction of helium is the ratio of the moles of helium to the total number of moles of gas.

PHe = XHe × Ptotal

= nHe / ntotal × Ptotal

= 90.2498 mol / 0.7458 mol) × 0.480atm

= 0.1608

Therefore, after rounding the answer to two significant figures, we find that the partial pressure of helium gas is about 0.161 atm.