Question

How many liters of carbon dioxide at 20 oC and 750 torr are produced when one gallon of toluene is burned

Answer 1

Convert 1 gallon of toluene to mL then to grams. Follow the procedure in the link below to calculate moles CO2, then use PV = nRT to convert to liters.
http://www.jiskha.com/science/chemistry/stoichiometry.html

Answer 2

can't convert ml to grams

Answer 3

You can if you know the density. Look at your post where you asked how to convert ml to grams. I worked the problem for you form scratch.

Answer 4

1 gallon toluene = about 3,785 mL
density = about 0.867 g/mL
mass toluene = 3785 mL x 0.867 g/mL = 3282 grams.
C7H8 + 9O2 ==> 7CO2 + 4H2O

moles toluene = grams/molar mass = 3282/92 = about 36 moles.
From the equation above, 1 mole C7H8 will produce 7 moles CO2; therefore, 36 moles toluene will produce 7 x 36 = about 250 moles CO2..

PV = nRT– V=250 X 8.314 X 293 / 750 = 812 L