Question

The gas tank of a 2015 Nissan Sentra holds 13.2 gallons. How many pounds of carbon dioxide are produced by burning an entire tank of gas? Express your answer rounded to the nearest tenth of a pound.

Answer 1

13.2 gallons=49.9 liters
the gas is the octan C8H18
the combustion of Octan equation is 
C8H18    +   25/2 O2-------------------> 8CO2         +  9 H2O
1mole                                                    8 moles
n(C8H18)=a                                              n(CO2)=b
so 
1 mole/a  = 8moles /b
and b= 8molesx a

we must find the value of a, molar volume of a gas is  v= 22.4l/mol=V/a, so a=V/v= 49.9/22.4= 2.23 moles

and b=8 x a=8x 2.23=17.85 moles
M(CO2)=m(CO2)/n(CO2)====> m=n x M=17.85 * (12+2x16)=  785.4 g

m(CO2)=785.4g = 1.57 pound