How many grams of oxygen are there in 100.0 grams of water? What percentage of the mass of water is oxygen?

percent O in H2O = (mass O/mass H2O)*100

%Oxygen = (16/18)*100 = ??

To determine the number of grams of oxygen in 100.0 grams of water, you need to know the chemical formula for water, H2O. It tells us that water consists of two hydrogen atoms and one oxygen atom.

To calculate the mass of oxygen, you can use the molar mass of oxygen, which is approximately 16.00 grams/mol. Since there is only one oxygen atom in water, we divide 16.00 grams/mol by the formula weight of water, which is approximately 18.02 grams/mol.

So the mass of oxygen in 100.0 grams of water is:
(16.00 grams/mol / 18.02 grams/mol) × 100.0 grams = 88.84 grams

Now, to find the percentage of the mass of oxygen in water, you divide the mass of oxygen (88.84 grams) by the mass of water (100.0 grams), and then multiply by 100 to get the percentage.

Percentage of the mass of oxygen in water:
(88.84 grams / 100.0 grams) × 100 = 88.84%

Therefore, there are 88.84 grams of oxygen in 100.0 grams of water, and oxygen makes up approximately 88.84% of the mass of water.