Answer:
Empirical SiCl3
Molecular Si2Cl6
Explanation:
Since it contains 79.1% chlorine, this means it contains (100 - 79.1)% silicon = 20.9% chlorine
To get the empirical formula, we firstly need to know the atomic masses of both chlorine and silicon. This is 35.5 and 28
We then divide the percentage abundances by the corresponding atomic masses.
Cl = 79.1/35.5 = 2.23
Si = 20.9/28 = 0.75
We then divide by the smallest, which is 0.75
Cl = 2.23/0.75 = 3
Si = 0.75/0.75 = 1
The empirical formula is thus SiCl3
To get the molecular formula:
(28+3(35.5))n = 269
134.5n = 269
n = 269/134.5 = 2
The molecular formula is Si2Cl6
