Question

Water is always made up of _____ part hydrogen to ______parts oxygen by mass.

Answer 1

I believe it's two part hydrogen and one part oxygen (H20)

Answer 2

The formula of water is
`H_(2)O`. Thus, molar ratio is 2:1.

Thus,

`n_(H):n_(O)=2:1`

Number of moles are related to mass and molar mass as follows:

`n=(m)/(M)`

Here, m is mass and M is molar mass

Molar mass of hydrogen is 1 g/mol and that of oxygen is 16 g/mol

`(n_(H))/(n_(O))=(2)/(1)`

Converting molar ratio into mass ratio as follows:

`((m_(H))/(M_(H)))/((m_(O))/(M_(O)))=(2)/(1)`

Also,
`\frac{m_{H* M_(H)}}{m_(O)* M_(O)}=(2)/(1)`

Putting the values of molar mass,

`(m_(H* 1 ))/(m_(O)* 16)=(2)/(1)`

Thus,

`(m_(H))/(m_(O))=(16* 2)/(1)=(32)/(1)`

Thus, water is always made up of 32 part hydrogen to 1 part oxygen by mass.