1.250g of an alloy which is 90.00% Ag and 10.00% Cu is dissolved in nitric acid yielding AgNO3 and Cu(NO3)2 solution. The nitrates are converted to Ag2SO4 and CuSO4 by heating with H2SO4. To the solution of the sulfates is added a piece of copper wire which reacts with the Ag2SO4 to precipitate all the silver. The reaction is: Ag2SO4 (aq) + Cu (s) > 2 Ag (s) + CuSO4 (aq). The resulting solution is treated with excess zinc to precipitate all of the copper (II) ion in the solution. What weight of copper will be precipitated?

Explanation:

Amount of silver

= 1.25 x .9 = 1.125

amount of copper = 1.25 x .1 = .125

equivalent weight of silver = 108

gram equivalent of silver in the alloy = 1.125 / 108 = .01041

This will precipitate in the form of copper in equivalent amount of copper

equivalent of copper precipitated = .01041

grm of copper for silver = .01041 x equivalent weight of copper

= .01041 x 63.5 / 2 = .3305 gram

Total copper precipitated

= .125 + .3305

= .4555 gm

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.