So my method doesn't satisfy you? All of my calculations were based on the molecular elements of H and O (H2, O2)
Where is the miscommunication?
A Mole is a particular number (6.022 × 10^23) . It is a count. It is not mass.
A mole is 602,200,000,000,000,000,000,000.
Therefore when stated that H2 has a mass of 2.016 kg/kmol, it means that 6.022 x 10^26 molecules of H2 has a mass of 2.016 kg.
A mole of H2O has 1 mole of H2 and .5 mole of O2
OR
To simplify it slightly but would not be found in nature... a mole of H20 has 1 mole of H2 and 1 mole of O
Since O is found as O2 in nature you assume the 6.022 x 10^23 O atoms bond together to form 3.011 x 10^23 molecules of O2. This is only half of a mol so to form a whole mol of O2 you need two mols of H2O. If you have 2 mol of H2O, then you have 2 mol of H2.
So 2 mol of H2 and 1 mol of O2 are formed from 2 mol of H2O.
Since these are just numbers the ratio of 2 mol H2 : 1 mol O2 is the same ratio as 2 kmol H2 : 1 kmol O2.
From Wikipedia - Water
H2O = 18.0153 g/mol or 18.0153 kg/kmol
Comparing this number to my previous calculations:
1 kmol of H2O = 18.0153 kg
2 kmol of H2O = 2*18.0153 = 36.0306 kg
Out of this, 4.032 kg is H2 and 32 kg is O2. THIS IS MASS. THIS IS NOT DENSITY.
DENSITY IS MASS PER VOLUME.
Wikipedia also gave a density of each of these elements H2 and O2 in grams/liter.
I inverted this to liter/kg by multiplying the gram/liter*1000 to kg/liter then divided 1 by that number.
Now that you have liter per kilogram, I multiplied it by how many kilograms we have to give liters.
Then determined the total percentages for each H2 and O2.
THE MATH IS SIMPLE BUT NOT AS SIMPLE AS 'CHRIST' DECLARES.
