Question

The empirical formula for a compound is CH2. If n is a whole number, which shows a correct relationship between the molecular formula and the empirical formula?
empirical formula mass / molecular mass = n

molecular mass = element mass / empirical formula mass ´ 100

subscript of H in empirical formula = 2  subscript of H in molecular formula

subscript of C in molecular formula = n  subscript of C in empirical formula

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Answer 1

Answer:

The corrects answer is last option.

The empirical formula of a compound = $CH_2$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{molecular mass}}{\text{empirical mass}}$

${\text{Molecular mass}=\text{Empirical mass}\times n$

Molecular formula will determined by multiplying the 'n' with subscript numbers of carbon and hydrogen in the empirical formula.

${\text{Molecular formula}=C_{n\times 1}H_{n\times 2}$

Answer 2

Answer:

subscript of C in molecular formula = n  subscript of C in empirical formula

Explanation: