# Question #97c8f

Sep 14, 2017

I think answer is 78 gm

#### Explanation:

% sum of all the elements = 100
% of H = 7.7
% left of remaining elements = 100-7.7 = 92.3%

now we find the % of other elements with help of ratio given

% of C = $3 \cdot \frac{92.3}{9}$ = 30.77%
% of O = $2 \cdot \frac{92.3}{9}$ = 20.51%
% of S = $4 \cdot \frac{92.3}{9}$ = 41.02%

now to finding empirical formula, we divide % by the atomic masses of respective element

C $\frac{30.77}{12}$ = 2.56
O $\frac{20.51}{16}$ = 1.28
S $\frac{41.02}{32}$ = 1.28
H $\frac{7.7}{1}$ = 7.7
now we divide all these %-mass ratio by the smallest %-mass ratio i.e. 1.28

C $\frac{2.56}{1.28}$ = 2
S $\frac{1.28}{1.28}$ = 1
O $\frac{1.28}{1.28}$ = 1
H $\frac{7.7}{1.28}$ =approx. 6

so the empirical formula is ${C}_{2} O S {H}_{6}$ and mass is 24 + 16 + 32 + 6 = 78 gm