What is the empirical formula for a compound that is found to contain 10.15 mg P and 34.85 mg Cl?

1 Answer
May 29, 2016

PCl_3

Explanation:

%P = (10.15*mg)/((34.85+10.15)*mg)xx100% = 22.6%

%Cl = (34.85*mg)/((34.85+10.15)*mg)xx100% = 77.4%

We use the percentages and assume 100 g of compound.

P: (22.6*g)/(30.9737*g*mol^-1) = 0.730*mol P

Cl: (77.4*g)/(35.45*g*mol^-1) = 2.18*mol Cl

We divide thru by the SMALLER molar quantity to give an empirical formula of:

PCl_3.