00:01
To determine the molecular formula, we first need to determine the empirical formula.
00:05
The empirical formula can be determined by converting the grams of carbon dioxide produced in the combustion reaction into moles carbon dioxide by dividing by its molar mass.
00:15
We can then convert the moles carbon dioxide into moles carbon, recognizing there's one mole carbon in one mole carbon dioxide.
00:23
This then will be the moles of carbon coming from carbon dioxide, but those are the moles of carbon originally found in the compound.
00:32
We then convert the grams of water into moles of water, dividing by the molar mass of water, and then convert the moles water into moles hydrogen.
00:42
These moles of hydrogen found in water were originally found in the compound.
00:47
So we have 0 .1 -30 moles of carbon for every 0 .391 moles of hydrogen.
00:54
But there's also oxygen in the compound to determine the amount of oxygen, or moles of oxygen, we need to convert these moles of carbon and hydrogen into grams.
01:07
Then we'll take the total mass of the compound that combusted, three grams, and subtract off the mass that is carbon and the mass that is hydrogen.
01:17
The difference will give us the mass that is oxygen...