A substance has an empirical formula of CH2 and a molar mass of 56 grams per mole. The molecular formula for this compound is

A

C4H8.

B

C4H6.

C

CH2.

D

C8H4.

The molecular formula for this compound is C4H8 (option A)

Explanation:

Step 1: Data given

Empirical formula of the compound is CH2

Molar mass of the compound is 56 g/mol

Step 2:

Since the empirical formula is CH2, this means we have 1 mol C for each 2 mol H

The molar mass of the empirical formula = 12 + 2*1 = 14 g/mol

To find the molecular formula we have to multiply the empirical formula by n.

n = molar mass of molecular formula / molar mass of empirical formula

n = 56 / 14

n = 4

Molecular formula = 4 * (CH2) = C4H8

We can check this by calculating the molar mass of this formula

4*12 + 8*1 = 48+8 = 56 g/mol

The molecular formula for this compound is C4H8 (option A)