Question

Silicon forms a compound with chlorine in which 5.6 gm of silicon is combined with 21.3gm of chlorine. Calculate the empirical formula of the compound. (At mass of si -28 cl - 35.5)

Answer 1

Given mass of silicon (Si) = 5.6 g
Given mass of chlorine (Cl) = 21.3 g
Molar mass of silicon = 28.09 g mol-1
Molar mass of chlorine = 35.5 g mol-1
n=Given mass/Molar mass
Number of moles (n) of silicon = 5.6/28.09 = 0.1993 moles

Number of moles of chlorine = 21.3/35.5 = 0.6 moles
Now , For silicon number of moles should be divided with least number of moles,
For silicon = 0.1993/0.1993 = 1
For chlorine = 0.6/0.1993 = 3
Hence , the empirical formula will be SiCl3.