The molecular weight of the compound having the empirical formula of CH2 was found to be 42.08. What is its molecular formula?
The empirical formula provides us with the simplest relation between the different atoms of a molecule. A molecular formula gives us the actual number of atoms in the molecule, although the ratio of atoms remains the same between a molecular formula and empirical formula.
Here, empirical formula = CH2
Empirical formula weight = number of atoms of carbon x atomic mass of carbon + number of atoms of hydrogen x atomic mass of hydrogen
= 1 x 12 + 2 x 1 = 14 g/mole.
The molecular formula weight is 42.08 g/mole.
Molecular formula = n x empirical formula,
where n = molecular formula weight / empirical formula weight
= 42.08 / 14 = 3 (approximately).
Thus, the molecular formula = 3 x empirical formula = 3 (CH2) = C3H6.
The required molecule is propene or propylene and has a molecular formula of C3H6.
Hope this helps.
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