Answer to Question #148842 in Physical Chemistry for Kay

Question

Ten grams of nitrogen is mixed with 5 grams of O2 and held at 25 degree Celcius at 0.750 bar.

a) What are the mole fractions of N2 and O2?
b) What are the partial pressures of N2 and O2?
c) What is the molar volume assuming the molecules do not interact?
d) What is the actual volume assuming the molecules do not interact?

Answer 1

a)      Moles of N₂ =10/28.02= 0.3569moles

Moles of O₂= 5/16= 0.3125 Moles

Total number of moles of two gases= (0.3569+0.3125) moles

                                                                     =0.6694moles

Mole fraction of N₂= 0.3569/0.6694= 0.5332

Moles of O₂= 0.3125/0.6694= 0.4668

b)     Partial pressure of N₂=0.5332×0.740192= 0.3947atm

[According to online conversion, 0.74bars=0.740192 atm]

Partial pressure of O₂= 0.4668×0.740192=0.3454 atm

c)      1 molar volume of the two gases at the prevailing conditions is 24.00L

PV=nRT

V=nRT/P

    n=0.6694moles

P= (0.3947+0.3454) =0.7401atm

V=0.6694×0.0821×298/0.7401

 =22.13L