There is also another question that asks "The actual ratio must be the ratio of two integers. Determine the most likely actual ratio of copper to sulfur, based on your answer above, and use it to write the empirical formula of your compound in the box".
What is the difference between the question asking the ratio of copper to sulfur and the question asking the ratio of two integers. sorry if this is a dumb question, i just want the clarification.
Calculate the molar ratio of copper to sulfur in the compound, expressed as a decimal number. (e.g.: 3.05, not 3.05:1) Show your calculation and round appropriately the ratio you get.
So, I've figured out my percentages and moles.
There is 83.74% Cu
And 21.97% S
In moles, if my calculations are correct, we would have:
0.309 g Cu * 1 mol Cu/63.546 g Cu = 0.005 moles
0.087 g S * 1 mol S/32.06 g S = 0.003 moles.
So to calculate the ratio, what would I do? I feel as if my mole calculation may be wrong, or there is an error. Can I get a ratio with such small numbers?
Thanks, I really do appreciate the help. Your time means a lot.
4 answers
.005/.003 = 5/3
Cu5S3
Cu5S3
5 molecules of Copper for every 3 of Sulfur
(a mol is just Avagadro's number of molecules, like saying a dozen)
(a mol is just Avagadro's number of molecules, like saying a dozen)
0.309 g Cu * 1 mol Cu/63.546 g Cu = 0.005 moles
0.087 g S * 1 mol S/32.06 g S = 0.003 moles.
Why did you round off so much; i.e., 0.309/63.54 = 0.00486 and
0.087/32.06 = 0.0027
So the ratio is 0.00486/0.0027 = 1.8 Cu to 1 S. I would think the most likely formula to be Cu2S. The difference between 1.8 and 2 is experimental error.
0.087 g S * 1 mol S/32.06 g S = 0.003 moles.
Why did you round off so much; i.e., 0.309/63.54 = 0.00486 and
0.087/32.06 = 0.0027
So the ratio is 0.00486/0.0027 = 1.8 Cu to 1 S. I would think the most likely formula to be Cu2S. The difference between 1.8 and 2 is experimental error.
2 answers