Question

Consider the combustion reaction for octane (C8H18), which is a primary component of gasoline. 2C8H18+25O2⟶16CO2+18H2O How many moles of CO2 are emitted into the atmosphere when 28.6 g C8H18 is burned?

Answer 1

Answer:

2 moles

Explanation:

2C8H18+25O2⟶16CO2+18H2O

First find the number of moles of C8H18 in 28.6 g of it.

n$(C_{8} H_{18}) = \frac{mass}{molar mass} = \frac{28.6 g}{114.2278 g/mol} = 0.250 mol$

Now to calculate how many moles of CO2 are produced by 0.25 of C8H18 you have to use the molar ratios taken from the stiochiometric ratios in the balanced chemical equations.

C8H18  :  CO2

    2      :    16

    0.25 :     x

then cross multiply

2x = 4

x = 2 mol