Monday, February 7, 2011

Silver Copper Replacement Lab

Copper Coil
     Copper wire reacts with aqueous silver nitrate. The relative amounts of the reactant and product are determined from the mass loss of copper wire, the starting mass of silver nitrate, and the mass of silver metal obtained. In the experiment, copper changed from its elemental form, Cu, to its blue aqueous ion form, Cu2+(aq). At the same time, silver ions (Ag+(aq)) were removed from solution and deposited on the wire in the elemental Ag metallic form.

     This lab took our class about 3 days to complete. Day number one, we got our materials ready and weighed out. We then took the silver nitrate (AgNO3) and mixed in distilled water until the AgNO3 had dissolved. After that, we placed the copper coil in the test tube as well and let it set until day two. Finally, we went back to class and used math with the balanced equation 2AgNO3 + Cu ----> Cu(NO3)2 + 2Ag and we formed predictions for how much silver should be formed and how much copper became Cu(NO3)2 in the reaction. Day number two rolled around and we observed a sort of crystal looking structure that had formed around the copper wire. We gently shook the test tube to dislodge this formation like the instructions requested. Then we set up a funnel with filter paper with a waste beaker underneath and we lifted the wire from the solution and dumped the remaining solution & silver mixture into the filter paper. Once it had drained we set both the wire & filter paper with the silver under the fume hood to dry. Day three and this was just to finish up the lab. We weighed the copper coil and recorded it's mass and did the same with the silver and filter paper. Now we had all the measurements needed to make out figures of how much Ag was formed & how much Cu was lost.

We used alot of moles in this lab.
There was lots of converting
grams to moles and back again.
     Our predictions said that we should expect to form about .7703g of Ag and loose about .2269g of Cu. With our measurements we did some more math to see if this prediction was correct. First was changed the number of moles of silver produced to moles and got .0103 mol. we did the same for number of copper consumed and that was recorded at .0036 mol. When divided by the smaller mole we got a 1 to 3 ratio of Cu to Ag. This information was compared to our predictions which had stated we would have a 1 to 2 ratio of Cu to Ag. When compared, we got 144 percent yield meaning that we got a considerable amount more silver than we had expected, but for the amount of copper used, we got 100 percent yield so we were right on target there. Overall, this lab, the Silver/Copper Replacement Lab, was a fun way for our class to learn more about mole ratios in a hands-on way.

1 comment:

  1. Hi there. Nice blog. You have shared useful information. Keep up the good work! This blog is really interesting and gives good details. copper wire suppliers, copper wire manufacturers.