Question

How many liters of oxygen are necessary to burn 30.4 liters of ethyl alcohol (C2H5OH)?

(Assume complete combustion)

Answer 1

C2H5OH + 3O2 ==> 2CO2 + 3H2O

You will need the density of ethyl alcohol. Use density to convert 30.4L to grams. mass = volume x density.
The convert g EtOH to mols. mols = g/molar mass.

Using the coefficients in the balanced equation, convert moles EtOH to moles O2.
moles O2 = moles EtOH x (1 mol O2/1 mol EtOH) = moles EtOH x (1/1) = ?

Then moles O2 x 22.4L/mol = L O2 required.
Post your work if you get stuck.