Four gases were combined in a gas cylinder with these partial pressures: 3.5 atm n2, 2.8 atm o2, 0.25 atm ar, and 0.15 atm he.
what is the total pressure inside the cylinder? 6.7 atm
what is the mole fraction of n2 in the mixture? 0.52 atm

2 equations: first, p subscript t equals p subscript 1 plus p subscript 2 plus p subscript 3 plus ellipses plus p subscript n. second: startfraction p subscript a over p subscript t endfraction equals startfraction n subscript a over n subscript t endfraction.
what is the mole fraction of o2 in the mixture? atm
what is the mole fraction of ar in the mixture? atm

A. 6.7 atm

B. 0.522

C. 0.418

D. 0.037

Explanation:

Dalton's law of partial pressure states that in a micture of non-reacting gases, the total pressure exerted by the mixture os the sum of their individual partial pressure

Mathematically, this can be written as:

PT = P1 + P2 + P3 + + Pn

Where PT is the total partial pressure

P1, P2, P3,...,Pn is the individual partial pressure of the gases that form the mixture.

A. The gases in this mixture is O2, Ar, N2 and He

O2 = 2.8 atm

Ar = 0.25 atm

N2 = 3.5 atm

He = 0.15 atm

PT = PO2 + PAr + PN2 + PHe

= (2.8 + 0.25 + 3.5 + 0.15) atm

=6.7 atm

B. Mole fraction of N2

P1 = x1*PT

PT = x1*PT + x2*PT + x3*PT +...+xnPn

Mole fraction, xn = Pn/PT

xN2 = 3.5/6.7

= 0.522

C. Mole fraction of O2

xO2 = 2.8/6.7

= 0.418

D. Mole fraction of Ar

xAr = 0.25/6.7

= 0.037