I lived in water all my life and watched my owner doing their chemistry work. Now I am curious how much oxygen there is in water compared to hydrogen. I can figure it out using the percent composition formula.
The formula we can use to find it is... Percent Composition by mass= (molar mass of element X number of that element) / molar mass of compound
So let's get started!
H = 1.01 (2) / 18.02 X 100% = 11.2% O = 16.00 / 18.02 X 100% = 88.8% Check your work: 88.8+11.2=100
Add in your variables into the equation and calculate for each element of the compound. Once you are finished to check your work by adding the percents of each element together, the sum should equal exactly one hundred (or around one hundred because of any rounding errors.)