Question

How many liters of CO2 at 0 °C and 380 torr are obtained in the reaction of 3 g of ethane with excess O2?

Answer 1

Mass of ethane = 3 g

Molar mass of ethane, C₂H₆ = 30.07 g/mol

Moles of ethane = mass/ Molar mass = 3g/ 30.07 g/mol= 0.0998 mol

Reaction is:

2C₂H₆ +7 O₂ 4CO₂ + 6H₂O

From reaction

2 mol of C₂H₆ produces 4 mol of CO₂

Thus, 0.0998 mol of C₂H₆ produces 4*0.0998/2 = 0.1995 mol of CO₂

Temperature (T)= 0^oC = 273 K

Pressure (P) = 380 torr = 380/ 760= 0.5 atm

Gas constant (R) = 0.0821L.atm/mol.K

Using Ideal gas equation

PV= nRT

V = nRT/ P

V=  0.1995 mol *0.0821L.atm/mol.K*273 K/ 0.5 = 8.94 L

Thus, Volume of CO₂ obtained in the reaction are 8.94 L