Question

You find that 7.36g of a compound has decomposed to give 6.93g of oxygen. The only other element is hydrogen. If the molar mass of the compound is 34.0g/mol, what is its molecular formula?

Answer 1

The molecular formula of this compound is
`H_(2)O_(2)`

Step-by-step explanation:

From the given,

Mass of compound = 7.36 g

Molar mass of compound = 34.0 g/mol

The mass of oxygen = 6.93 g

The hydrocarbon contains only hydrogen and carbon.

Mass of hydrogen + Mass of oxygen = 7.36 g

Mass of hydrogen + 6.93 g = 7.36 g

Mass of hydrogen = 7.36 - 6.93 = 0.43g

Molar mass of hydrogen = 1.0 g/mol

Molar mass of oxygen = 16 g/mol

`Number\,of\,moles\,of \,Oxygen=6.93g*(1)/(16)=0.43mol`

`Number\,of\,moles\,of \,hydrogen=0.43g*(1)/(1)=0.43mol`

Now divided each one by 0.43

Oxygen:

`(0.43)/(0.43)=1`

Hydrogen :

`(0.43)/(0.43)=1`