Question

1. The partial pressure of CHR) is 0.175 atm and that of O.18) is 0.250 atm in a mixture of the two gases. [-15 points;-5 points each] a. What is the mole fraction of each gas in the mixture? next →

Answer 1

According to Daltons law,the total pressure exerted by a mixture of two or more non-reacting gases in a definite volume is equal to the sum of partial pressures of the constituent gases

Total pressure, Patm = PCH4 + PO2 = 0.175 +0.250 = 0.425 atm

Ptotal = 0.425 atm

a). The partial pressure of CH4, PCH4 = Ptotal * molef raction of CH4

               mole fraction of CH4 = PCH4/ P_TOTAL = 0.175/0.425 = 0.4112

The partial pressure of PO2 = Ptotal * mole fraction of O2

               mole fraction of O2 = PO2/P_TOTAL = 0.250/0.425 = 0.5882

b) from ideal gas equation, PV = nRT

total number of moles, n = PV/RT = 0.425*10.5 /(0.0821*338) = 0.161 MOLES

c). The number of moles of CH4 = mole fraction of CH4 * total number of moles

                               = 0.4112 * 0.161 = 0.0662 moles

   mass of CH4 = molar mass * number of moles = 0.0662 * 16 = 1.059 grams

The number of moles of O2 = mole fraction of O2 * total number of moles

                               = 0.5882 * 0.161 = 0.0947 moles

mass of O2 = molar mass * number of moles = 0.0947 * 32 = 3.030 grams