MHS Chemistry
The Copper Cycle - Analysis

Name: _____________________
Section: A B C D E F G

Description Value Units
Initial mass of copper    
Mass of filter paper    
Final mass of filter paper + copper    

Answer each of the following questions clearly and completely. You must show your work for the questions with a * in order to get credit.

*1. Determine the mass of copper recovered.

*2. Determine the percent recovered of your original mass.

*3. Briefly explain why your percentage was or was not 100 %.

*4. How many moles of copper did you start with?

In step 2, you added nitric acid to the copper wire. The reaction was

Cu(s) + H1+(aq) + NO31–(aq) ---> Cu2+(aq) + N2O4(g) + H2O(l)
copper nitric acid copper (II) dinitrogen tetroxide water

*5. Assuming all the oxygen atoms in this reaction are oxide ions (O2–), what is the charge on each nitrogen atom before the reaction?

*6. What is the charge on each nitrogen nitrogen after the reaction?

7. Was nitrogen oxidized or reduced? Explain your reasoning.

In step 9 (step 1 one on day 2), aluminum foil was added to the blue-green copper solution until the solution was clear. The reaction was:

3Cu2+(aq) + 2Al(s) ---> 3Cu(s) + 2Al3+(aq)

*8. What were the minimum number of moles of aluminum needed to react all your copper (according to your answer to #4)?

*9. Calculate what this mass of aluminum was.

10. Was aluminum oxidized or reduced in the is reaction? Explain your reasoning.



[Copper Cycle lab][MHS Chemistry page]