Using the mass of the copper in the crucible (first mass in the table), and the mass of the crucible with compound (last mass you measured), calculate the mass of sulfur present in your product. Then find the percentage (by mass) of copper and the percentage (by mass) of sulfur in the product.

Question

so far I have,

Initial crucible weight w/ copper = 17.914 g
Mass of crucible w/ compound = 18.001 g
So we have the 0.087 g of sulfur.

How would I find the percentages (by mass) if I were to attempt this?
Would i need the empirical formula of this compound to further solve this? What is the equation I would use? Thank you!!

Answer 1

How much Cu did you have?
%Cu = (mass Cu/mass copper sulfide)*100 = ?
% S = (mass S/mass copper sulfide)*100 = ?

Answer 2

That makes sense. I was missing that value. The weight of Cu would be 0.309 g. That is how much I have.
So,
%Cu = (0.309/0.087) x 100 ?
Are those the right values?

Answer 3

Wait, that's how I would get sulfur right? The %Suflur=(0.309/0.087) x100?

Which value would I use for Cu?

Answer 4

Neither one is correct.
Mass Cu = 0.309
mass S = 0.087
mass compound is 0.309 + 0.087 = 0.396
%Cu = (0.309/0.396)*100 = ? etc