1. A chemistry student determined the empirical formula for titanium sulfide (TixSy). To do so, she reacted titanium with excess sulfur in a crucible, and recorded the following data:
Weight of crucible g 
Weight of titanium g
 Weight of crucible and product g
What is the empirical formula of titanium sulfide?
Determine the mass of sulfur: ( ) = g
Convert each the masses to moles:
For Ti:
For S:
Divide by the smallest:
Therefore the empirical formula is: TiS2

2. A compound with a percent composition by mass of 24. 61% C, 2
A compound with a percent composition by mass of 24.61% C, 2.75% H, and 72.64% Cl has a molar mass of g/mol. What is the molecular formula of the compound?
If you use 100 grams, the percentages become grams. C:
÷ 2.05
= 1
X 3
= 3 H:
÷ 2.05
= 1.33
X 3
= 4
Cl:
= 1
÷ 2.05
X 3
= 3
Therefore the empirical formula is C3H4Cl3
with an empirical formula mass of g/mol
To find the molecular formula divide the molar mass by the empirical mass:
÷ = 2 and use the answer as a multiplier to get C6H8Cl6