Water is 2 parts of hydrogen and 1 part oxygen. for one molecule of water each atom has the atomic mass unit, u,shown. what percent o the mass of a water molecule is hydrogen

Question

asked Aug 23, 2019 76.6k views

2 Answers

Ralph N · Answer 1 · 2019-08-28T01:50:31+0000

Answer:

11.19 %

Explanation:

1 molecule water = 2 H + 1 O

If H = 1.008 u and O = 16.00 u, then

Water = 2H + 1 O = (2 × 1.008 u) + (1 × 16.00 u) = 2.016 u + 16.00 u = 18.02 u

The formula for mass percent is

$\% \text{ by mass} = \frac{\text{Mass of H}}{\text{Total mass}} * 100 \%$

So,

$\%\text{ H} = \frac{\text{2.016 u}}{\text{18.02 u}} * 100 \% = 11.19 \%$