Question

Based upon elemental analysis, the empirical formula for an unknown compound was calculated to be CH2. Mass spectrometry analysis reveals the compound to have a molar mass of approximately 42 g/mol. What is the molecular formula for the compound

Answer 1

Answer:

C3H6

Explanation:

42g/mol=molar mass

14g/mol= emperical mass

42/14=3

3 times emperical

Answer 2

Answer:

C3H6

Explanation:

We can obtain the molecular formula by using the empirical formula and the molar mass in combination.

This is shown below:

[CH2]n = 42g/mol

We then add the atomic masses of carbon and hydrogen and multiply by n to give the value of n .

n[12 + 2(1)] = 42

14n = 42

n = 42/14 = 3

The molecular formula is thus [CH2]3 = C3H6