Question

A flask, at 25.0 oC, with a volume of 1.00 L is filled with an unknown gas to a pressure of 100.00 kPa. By weighing the flask before and after filling, it is found that the mass of the gas is 0.16 g. i. How many moles of gas are in the flask? ii. What is the molar mass of the gas?

Answer 1

From the data Pressure (P) = 100kPa = 0.99 atm ( we know that latm = 101.33 kPa > 100 kpa x latim cm = 0.99 atm ) 101.33 KB Temperature (T) = 25C - 125+273)K = 298K Volume (V) = 21 mass of the gas = 0.16g = weight of gas ÿ moles of gas we know that ideal gas equation PV = nRT 5 In- PV RT where R=gas constant 50.0821 L.atm/kimol na number of moles, p=0.99 atm, V = 1L T = 298k. substitute all the values in equation n= (6.99 atm) (12) - 0.0821 leto ) (298 k) 0.04 mol á moles of gas = 0.04 mol

A ☺ we know that number of moles - weight molar mass - 3 molar mass = weight o humber of moles → molax mass = 0.169 .o.ohmol = 4g/mol molar mass of gas= 49/mol