Question

Consider the following balanced reaction: 2C2H6(g) + 7O2(g) ->4CO2(g) + 6H2O(g)

How many liters of carbon dioxide at STP are produced when 60.0 liters of C2H6 (g) are combusted?

Answer 1

first let me write the STP conditions

P = 1 atm

T = 273.15 K

R = gas constant = 0.0821 L atm /mol-K

first find the no of moles of C2H6 using PV = nRT

V = 60.0L rest all the terms take from the above

1 x 60.0 = n x 0.0821 x 273.5

n = 60 / 22.45

n = 2.67 mole

now look at the balanced equation

2C2H6(g) + 7O2(g) ->4CO2(g) + 6H2O(g)

2 moles of C2H6 is giving 4 moles of CO2

1 mole of C2H6 is giving 2 mole of CO2

2.67 moles of C2H6 will give 2 x 2.67 = 5.34 mol of Co2

now

use n = 5.34 sue the remaining parameters from the STP and find the volume

PV = nRT

1 x V = 5.34 x 0.0821 x 273.5

V = 120 L