Question

The ratio of carbon atoms to hydrogen atoms to oxygen atoms in a molecule is 2 to 4 to 1

What is the molecular formula of this substance if its molar mass is 88 grams.

Answer 1

`C_(4) H_(8) O_(2)`

Step-by-step explanation:

Setting up ratio:

Carbon : Hydrogen : Oxygen

2 : 4 : 1

As there are two carbon atoms, four hydrogen atoms and one oxygen atom,

therefore the formula becomes:
`C_(2) H_(4) O`

The Mr would be: (12 x 2) + 4 + 16

= 44 g/mol

Molecular formula:

`(C_(2) H_(4) O)_(n)`

n = 88/44

n = 2

Thus:

`(C_(2) H_(4) O)_(2)`

=
`C_(4) H_(8) O_(2)`

Answer 2

C4H8O2

Step-by-step explanation:

The empirical formula is C2H4O1 [C/H/O is 2/4/1]

As written, the molar mass is (2*12) = 24, plus (4*1) = 4, plus (1*16) = 16, for a total of 44 grams/mole. Two units of C2H4O1 would be 88 grams/mole, which is what is needed.

The molecular formula is C4H8O2.