This balance equation shows the burning of octane in air. 2C8H18 + 25O2 ----> 16CO2 + 18H2O. How many grams of carbondioxide will be produced when 1 mole of octane burns completely?

Answer 1

You have the equation.
Convert 1 mol octane to mols CO2. That will be 1 mol C8H18 x (16 mols CO2/2 mol C8H1*) = 1 x (16/2) = 8.
Then g CO2 = mols CO2 x molar mass CO2.