Question

QUESTION THREE a) A mixture of gases consists of 30 percent hydrogen, 40 percent helium, and 30 percent nitrogen by volume. Calculate: i) The mass fractions and ii) The apparent molecular weight of this mixture. (10 marks) b) A 30 percent (by mass) ethane and 70 percent methane mixture is to be blended in a 100 m tank at 130 kPa and 250 °C. If the tank is initially evacuated, to what pressure should ethane be added before methane is added? (10 marks) [20 marks]

Answer 1

Solution H₂ = 30% N2 = 30%. + Me Yoy L u - molarmare a 28 0 mars fraction of gas (can) (gas), X (4) Igory+gasy go хие yox y = 100 30 uo 700 X 2 + 100x4 + 700 X 28 = 1.6 .bt 1.6+ 8.4 = 1.60 10.6 Ixne = 0.151 ath 3 X 2 -3X2 + .uxu + 28 x. 3 XH2 -0.057 XN2 3X28 3x2 + 4x4 + 28x3 1XN₂ = 0.792

Apparant moliculas caight of mixturu (m) = (%)X(gas) +(%) (az) + m =.3x2+.uxut. 3x28 m = 10.6 (0 30% ethan + 70% methand HP=130kPa J V= 100 m3"?T=523k 100 m3 using Daltor's law of Partial bussene "Ptatal = Pogos & Press + Pyrzt --- Pgas, = X X Platel xy mole fraction of (gas) This initally find out mole fraction of gas (Mchu = 16 (m cathe = 30

(XC) chut 14 Х-фо Х:34:20 1L (2) охо 3Х30 +2°ус П. 20-2. 4.0 20.7 (сил) = 0-SS (1), - ич . Р Ge — ччL X130 = $9.98 ква Рchu SS ЧX130 - 22:0К This is the pressun of invidual gas in the tank.