Chemistry problem...please help!! : (?

Question

1.Assuming that gasoline is C8H18 and has a density of 0.703 g/ml, how many liters of CO2 will be produced from the consumption of 2.5 gallons of gasoline at standard condtions ?

any help would be greatly appreciated!

Answer 1

This is not that hard; you need the balanced equation for the reaction and the number of moles of gasoline in 2.5 gallons.

The balanced equation is:

2 C8H18 + 25 O2 ---> 16 CO2 + 18 H2O

Now, to get moles of gasoline in 2.5 gal, use standard conversion factors for volume, & the density and molar mass of C8H18:

(2.5 gal x 3785ml/gal x 0.703g/ml)/[(8 x 12.01) + (18 x 1.01)] =

6652g/114.3g/mole = 58.2 moles

Now use the number of moles and the reaction ratios from the balanced equation to get moles of CO2 produced:

58.2mole x (16/2) = 466 moles CO2

Now convert moles of CO2 to liters; since it was specified that the gas was at STP, you can use the rule that a mole of any gas at STP = 22.4 liters:

466moles x 22.4l/mole = 10440 liters

Answer 2

Balanced combustion equation first.

2C8H18 +25 O2 > 16CO2 + 18H2O

Now, try it.