Calc % Ag in Alloy: 0.6353g Ag2/ 0.5000g alloy x 100% = 12.9%

AI Thread Summary
To calculate the percentage of silver in a copper-silver alloy, the total mass of the solid sulfides (0.7300 grams) is used to determine the mass of silver. The calculations involve converting the mass of Ag2S to moles and then to grams of silver, resulting in 0.6353 grams of silver. The percentage of silver in the alloy is then calculated using the formula: (mass of Ag/mass of alloy) x 100%, yielding 12.9%. The discussion highlights the need for clarity in the initial steps of the calculation and confirms the correctness of the approach taken. The final answer is that the alloy contains 12.9% silver.
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Homework Statement


An alloy of copper and silver weighing 0.5000 grams is dissolved in HNO3 and treated with H2S to precipitate both CuS and Ag2S. It is found that the solid sulphides weigh 0.7300 grams. Calculate the percentage of Ag in the alloy. (12.9 %)

2Ag+(aq) + H2S(aq)→ Ag2S(s) + 2H+(aq)
Cu+2(aq) + H2S(aq)→ CuS(s) + 2H+(aq)

Homework Equations


mass of Ag/mass of alloy = % of Ag

The Attempt at a Solution


I'm not too sure how to start this question…

So far, I have

0.7300 g Ag2S x 1 mol / 215.74 g Ag2
= 2.945 x 10-3 mol Ag2S

2.945 x 10-3 mol Ag2S x 215.74 g Ag2/ 1 mol Ag2S
= 0.6353 g Ag2I'm not sure if I'm on the right track here?
 
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You have a system of two equations in two unknowns.
 
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