Question

Quantitative analysis of an organic compound (X) shows the following percentage composition. 
C: 14.5% 
Cl: 64.46% 
H: 1.8% 
Empirical formula mass of the compound (X) is:

Answer 1

Correct Answer: 1655

Element	Percentage by Mass	Molar Ratio	Simplest Ratio
C	14.5	$ \frac{14.5}{12} = 1.2 $	$ \frac{1.2}{1.2} = 1 $
Cl	64.46	$ \frac{64.46}{35.5} \approx 1.8 $	$ \frac{1.8}{1.2} = 1.5 $
H	1.8	$ \frac{1.8}{1} = 1.8 $	$ \frac{1.8}{1.2} = 1.5 $
O	19.24	$ \frac{19.24}{16} \approx 1.2 $	$ \frac{1.2}{1.2} = 1 $

Procedure:

1. Calculate the molar ratio by dividing the percentage composition of each element by its atomic mass.
2. Determine the simplest ratio by dividing each molar ratio by the smallest molar ratio calculated.
3. Convert to whole numbers by multiplying all simplest ratios by a common factor if fractions are present.

Empirical Formula: $ C_2H_3Cl_3O_2 $

Molar Mass: $ 165.5\,\text{g/mol} $ (or $ 1655 \times 10^{-1}\,\text{g/mol} $)