Two separate syntheses produce samples of a copper–sulfur compound
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
Two separate syntheses produce samples of a copper–sulfur compound. The first synthesis yields 0.635 g of copper chemically combined with 0.160 g of sulfur. The second synthesis produces 1.270 g of copper combined with an unknown mass of sulfur.
(1) Calculate the mass of sulfur that must be present in the second sample for both samples to represent the same compound.
(2) Using your result from part (a), show quantitatively that the mass ratio of copper to sulfur is constant for the two samples.
(3) Determine the empirical formula of the copper–sulfur compound based on the mass data for the first sample, showing all mole calculations.
(4) Explain how the results you obtained illustrate the law of definite proportions for this compound.