What is the percent by mass of oxygen in H2O?
A. 11.1% O
B. 50.0% O
C. 88.9% O
D. 95.0% O
I think C
Yes it is 88.9%!
To find the percent by mass of oxygen in H2O, you first need to determine the molar mass of H2O.
The molar mass of hydrogen (H) is 1.01 grams per mole, and there are two hydrogen atoms in H2O. The molar mass of oxygen (O) is 16.00 grams per mole. Adding these together, we get:
Molar mass of H2O = 2(1.01 g/mol) + 16.00 g/mol = 18.02 g/mol
Next, we need to find the percent by mass of oxygen in H2O. To do this, we divide the molar mass of oxygen by the molar mass of H2O and multiply by 100:
Percent by mass of oxygen = (16.00 g/mol / 18.02 g/mol) × 100 ≈ 88.9%
So, the correct answer is C. 88.9% O.