Question

A closed container with a mixture of hydrogen, helium, and argon has a total pressure of 2.55 atm. The partial pressure of hydrogen is 0.700 atm and the partial pressure of argon is 705 mm Hg. What is the partial pressure of helium?

Answer 1

Dalton's law of partial pressures. The total is the sum of each.
ptotal = pH2 + pAr + pHe

Answer 2

Total pressure=partial pressure of mixture
Total pressure=partial pressure of Hydrogen +PHe+Pa
Partial pressure of Hydrogen= 0.700 atm
Total pressure=2.55
Partial pressure of AR= 705 mm, lets convert that to atm. 1 atm=760 mm Hg
705/760mm of Hg
705/760=partial pressure of AR= 0.92763158=0.92
2.55=0.700 atm +Partial Pressure of He +0.92
0.7+0.928=1.628
2.55= 1.628 + partial Pressure of He
subtract 1.628 from 2.55, 2.55-1.628=0.930
So the answer would be partial pressure of helium is 0.930 atm.