Chemical Reactions of Copper: Key
Copper Recycling Lab
(Day 1)
Day 1 Data
1. Write the balanced chemical equation for the reaction between copper and nitric acid
(HNO3). For all reactants and products, include the state of matter.
1. Cu (s) + 4 HNO3 (aq)  Cu(NO3)2 (aq) + 2 NO2 (g) + 2 H2O (l)
2. Cu(s) + 4H+(aq) + 4NO3-(aq)  Cu2+(aq) + 2NO3-(aq) 2NO2(g) + 2H2O (l)
Cancel spectators: NO3Cu(s) + 4H+(aq) + 2NO3-(aq)  Cu2+(aq) + 2NO2(g) + 2H2O (l)
Copper Recycling Lab
(Day 2 & 3)
1. What evidence was there that a chemical reaction took place in conversion 1?
Formation of Cu(NO3)2 solution (blue), release of NO2 (g) brown, heat change and condensation
2. Identify the type of chemical reaction for conversion 1.
Single Displacement
3. What was the limiting reactant in conversion 1 and how can you tell?
Cu (s) – All of the copper wire is used up
4. Classify the product in the flask after conversion 1 as a pure substance, homogeneous
mixture, or heterogeneous mixture.
Homogeneous Mixture
5. Why is the copper (II) nitrate not visible once the reactions are done? Where did it go?
It is an aqueous solution – is dissolved
6. If the experiment stopped after conversion 1, what method could be used to recover this
compound?
Evaporate off the water
7. Assuming no copper has been lost; calculate the mass of copper (II) nitrate that could be
recovered after conversion 1.
1.5 g Cu
1 mol Cu
1 mol Cu(NO3)2
187.5 g Cu(NO3)2
= 4.43 g Cu(NO3)2
63.5 g Cu
1 mol Cu
1 mol Cu(NO3)2
8. Calculate the number of copper atoms you started with before any reactions were
performed.
1.5 g Cu
1 mol Cu
6.02 x 1023 atoms Cu
= 1.42 x 1022atoms Cu
63.5 g Cu
1 mol Cu
9. Based on the law of conservation of mass, how many copper atoms should be recovered at
the end of this experiment?
1.42 x 1022 atoms Cu
10. What evidence was there that a chemical reaction took place in conversion 2?
Formation of a Precipitate
11. Identify the type of chemical reaction for conversion 2.
Double Replacement
12. Based on what you know about the lab, what was the limiting reactant in conversion 2?
Copper (II) Nitrate
13. Classify the product in the flask after conversion 2 as a pure substance, homogeneous
mixture, or heterogeneous mixture.
Heterogeneous Mixture
14. Assuming no Cu has been lost; calculate the mass of dry copper (II) hydroxide produced
in conversion 2.
4.43 g Cu(NO3)2
1 mol Cu(NO3)2
1 mol Cu(OH)2
97.5 g Cu(OH)2
= 2.30 g Cu(OH)2
187.5 g Cu(NO3)2
1 mol Cu(NO3)2
1 mol Cu(OH)2
15. What is the purpose of the cold-water bath during conversion 2?
To absorb the heat released by the reaction
16. Write the chemical equation for the neutralization reaction in conversion 2.
HNO3 (aq) + NaOH (aq)  NaNO3 (aq) + H2O (l)
17. Why does the neutralization reaction occur before conversion 2 begins?
To use up all the nitric acid
18. What evidence was there that a chemical reaction took place in conversion 3?
Formation of a precipitate, color change
19. Identify the type of chemical reaction for conversion 3.
Decomposition
20. Classify the product in the flask after conversion 3 as a pure substance, homogeneous
mixture, or heterogeneous mixture.
Heterogeneous Mixture
21. After conversion 3, the copper (II) oxide precipitate is rinsed, and the excess is
decanted three times. Which contaminants(s) were being removed?
Sodium hydroxide, Sodium Nitrate
Copper Recycling Lab
(Day 4)
1. What evidence was there that a chemical reaction took place in conversion 4?
Color Change
2. Identify the type of chemical reaction for conversion 4.
Double Replacement
3. Classify the product in the flask after conversion 4 as a pure substance, homogenous
mixture, or heterogeneous mixture.
Homogeneous Mixture
4. What evidence was there that a chemical reaction took place in conversion 5?
Formation of solid copper, color change
5. Identify the type of chemical reaction for conversion 5.
Single Displacement
6. Classify the product in the flask after conversion 5 as a pure substance, homogeneous
mixture, or heterogeneous mixture.
Heterogeneous Mixture
7. Why shouldn’t there be any blue color remaining in the solution after conversion 5?
Copper (II) Chloride is blue  Should be limiting reactant
8. Which contaminant(s) are being rinsed away with hot water after conversion 5?
Aluminum Chloride, Hydrochloric Acid
9. Why does the secondary reaction take place a long with conversion 5?
The aluminum reacts with the excess hydrochloric acid from conversion 4.
Copper Recycling Lab
(Day 5)
1. What would a bluish or greenish colored copper indicate after it has been dried?
Contamination of copper (II) chloride
2. Calculate the percent recovery of copper by mass. (Show Your Work!!)
Mass Recovered
x 100 =
Mass Original Copper
3. Calculate the percent error. (Show Your Work!!)
100% - % Recovery =
4. What are two errors that could have made the percent recovery of copper too high?
Water on Product, Copper (II) Chloride on Product
5. What are two errors that could have made the percent recovery too low?
Loss of Copper in Procedure
6. Which errors identified above fit the results? Why?