00:01
For this question here, we'll start by calculating the moles of carbon from the 0 .1486 grams of carbon dioxide, because all of the carbon dioxide is present in the carbon dioxide, so molar mass here, 44 grams of co2 and one mole, and in one mole of co2, we have one mole of carbon.
00:26
That gives us 0 .00338 moles of carbon.
00:33
Then we can calculate similarly the moles of hydrogen as all the hydrogen is present in the water from the 0 .069 grams of water, molar mass, water is 18 grams per mole.
00:53
And in one mole of water, we see that we have two moles of hydrogen.
00:57
And this works out to 0 .0067 moles of hydrogen.
01:04
Now we still need to find the amount of oxygen.
01:09
So let's find the mass of carbon, which is equal to 0 .00338 moles, one mole of carbon, molar mass 12 .0 grams, and this gives us 0 .406 grams of carbon.
01:32
And then we'll find the mass of the hydrogen.
01:38
0 .00677 moles of hydrogen.
01:43
1 mole of hydrogen, 1 .0 grams, 0 .00677 grams of hydrogen.
01:51
And then the mass of oxygen would be the mass of the sample minus the mass of the carbon, minus the mass of the hydrogen, to give us 0 .056, 6, 7 grams of oxygen...