Test Index

JAMB Chemistry 2014 Paper

Question : 39

Total: 45

[C = 12, H = 1]

Solution:

Concept:

The molecular formula is a whole number multiple of the empirical formula, determined using the molecular mass from vapour density.

Explanation:

Molecular mass

= 2 \times \text{vapour density}

= 2 \times 39 = 78

The empirical formula is

\mathrm{CH}

, so its formula mass

= 12 + 1 = 13

The molecular formula is

(\mathrm{CH})_n

Thus,

13n = 78

n = \frac{78}{13} = 6

So molecular formula

= \mathrm{C}_6\mathrm{H}_6

Answer:

\mathrm{C}_6\mathrm{H}_6

Go to Question:

Prev Question

Next Question