Question

A mixture of argon and hellum gases, in a 8.76 L flask at 77 °C, contains 7.12 grams of argon and 1.24 grams of hellum. The partial pressure of hellum in the flask isl a m and the total pressure in the flask is Submit Answer Retry Entire Group 4 more group attempts remaining

Answer 1

is. Griven the of Argon and in a 8.76 L mixture contains 7.12 grams 1.24 gm of Helium gas flask at 77°C Ainki , ulе. Кури) No. of moles = Griven Weight - Molecular weight lingm) briven weight of Ar = 7.12 gm molar mass of Art 40 gm a No. of moles, nq = 7012 mole - ni = 0.178 mole briven weight of He = 1.24 gm. molare mass of He = 4 gm 4 No. of moles, n2 = 1. 24 40 - n = 0.31 moles

. Hence, Total no. of moles of gases in the flask, n = n, en 2 u n = 0.178 + 0.31 - n = 0.488 mole volume of Flack, w = 8.76 L Temperature , T = 77°C = 774 273 K _ T 350K Cras be a constant, R = 0.0821 L-atm /mol K Using Ideal gas equation, - PV = nRT 9 P= nRT = 0.488 x 0.0821 x 350 8.7.6. = 1.6 atm

Hence, Total pressure in the flask is - 1.6 atm Using Dollon's Lawo of Partial Press wce, Partial pressure of any compent A is a mixture is I Partial Pressure 1 = 1 Mole fractional Total ] l of A l of A l Pressure) mole fraction of Ar = 0.178 0.438 = No. of moles of Ar = 0.365 Total no. of moles Hence M. Ar = 0.365 Similarly, mole fraction of He = 0.31 0.488 0.635 Hence x He = 0.635

Hence flask Partial Pressure of = .1 mole fraction & t of te Helium in the Totel pressure) 0. 6. 3 5 x lob atm = total And 1.016 atm pressure in the flask is 1.6 atm