We have to calculate the mole fractions first before we can get the partial pressures of other gases
Xa = na/nt where Xa is the mole fraction, Na is the number of moles of gas A and nt is thetotal number of moles of gasses
We are given the masses of the gasses so we can start by calculating the number of moles.
n of boron trifluoride = m/M
n = 8.32 g/67.81 g/mol
n=0.1227 mol
n of chlorine pentafluoride= m/M
n=18.9/130.445
n=0.1149 mol
Mole fraction of boron trifluoride = 0.1227/(0.1227 + 0.1149)
= 0.5164
Mole fraction of chlorine pentafluoride = 0.1149/ (0.1227 +0.1149)
=0.4836
Partial pressure of boron trifluoride:
pV= nRT
p = nRT/V
p = (0.1227 x 0.08206 x 288)/ 8
p= 0.3625 atm
Partial pressure of chlorine pentafluoride
p= (0.1149 x 0.08206 x 288)/ 8
p =0.3394 atm