a compound of carbon ,hydrogen and oxygen contains 54.55%carbon 9.09%hydrogen and the rest is oxygen determine the molecular formula of the compound given that its relative molecular mass (c=12,o=16,h=1)
Let's assume we have 100g of the compound.
54.55% of 100g is carbon, which is 54.55g.
9.09% of 100g is hydrogen, which is 9.09g.
The rest (100g - 54.55g - 9.09g = 36.36g) is oxygen.
Next, we need to calculate the number of moles for each element:
- Moles of carbon: 54.55g / 12 g/mol = 4.55 mol
- Moles of hydrogen: 9.09g / 1 g/mol = 9.09 mol
- Moles of oxygen: 36.36g / 16 g/mol = 2.27 mol
The ratio of the elements in the compound is then:
C: 4.55 / 2.27 = 2
H: 9.09 / 2.27 = 4
O: 2.27 / 2.27 = 1
This gives us the empirical formula as C2H4O.
To find the molecular formula, we need to know the relative molecular mass (RMM) of the compound.
RMM = (2 x 12) + (4 x 1) + (1 x 16) = 44
The molecular formula is then calculated by dividing the RMM by the empirical formula mass (EFM):
Molecular formula = RMM / EFM
Molecular formula = 44 / 44 = 1
So the molecular formula is the same as the empirical formula: C2H4O.