In: Chemistry
If your favorite silver jewelry ever tarnishes and you happen to have some aluminum foil on hand, you can actually get rid of some of that tarnish. The tarnish here is actually silver sulfide. If you put the jewelry and aluminum into a dish with enough water to cover them both, the following reaction will occur: 3Ag2S + 2Al --> 6Ag + Al2S3. If you have a total of 5.0 g of Al foil accessible to you, how many grams of Ag2S (thus, loosely speaking, how much jewelry) could you theoretically "clean"? You must show all work clearly and in detail to receive credit. All numbers immediately following elemental symbols should be understood as subscripts. (NOTE: If you try this at home, you may want to dissolve some baking soda in your solution to help neutralize the smell, because some of the sulfur here will escape as a gaseous product and not smell very pleasant!)
Molar mass of Ag2S = 247.8 g/mol
Molar mass of Al = 27 g/mol
3Ag2S + 2Al ------------> 6Ag + Al2S3
3 mol 2 mol
3 x 247.8 g 2 x 27 g
? 5 g
? = 3 x 247.8 g of Ag2S x ( 5g/ 2 x 27 g)
= 68.83 g of Ag2S
Therefore,
68.83 grams of Ag2S could be theoretically "clean".