Cu Again: Reactions of Copper
Lynna Jezek*, Long Nguyen
CHEM 111-502
Introduction:
The element copper has proven to be of great use to human civilizations through time; from the first bronze smelted by the Sumerians to copper’s practicality in today’s industry-driven world, copper has become essential to human life. Copper’s use in industry (such as its great conductivity of heat and electricity) has driven many scientists to study the Copper Cycle, or how copper behaves as a response to different chemical environments. While oxidized copper ore is easily distinguished by its blue-green color, the complete Copper Cycle occurs with copper in both its elemental and oxidized states, which will be fully explored by sending copper metal through …show more content…
The solution was cooled, and 5 mL of distilled water was added to the beaker along with a magnetic stir bar for the final reaction. A mass of 528 mg of 20 mesh zinc was weighed out and added to the mixture; the solution was stirred for 15 minutes when it became colorless. Finally, the solution was decanted and 5 mL of 6 M HCl was added to complete the reactions of the Copper Cycle. The leftover solid was recovered using an aspirator, Büchner funnel, and distilled water to wash any remaining copper onto the funnel filter. The final mass of the copper metal was used to calculate the percent yield of copper in this series of reactions. Observations for each reaction step were recorded.
1 Cu (s) + 4HNO3 (aq) → Cu(NO3)2 (aq) + 2NO2 (g) + 2H2O (l)
2 Cu(NO3)2 (aq) + 2NaOH (aq) → Cu(OH)2 (s) + 2NaNO3 (aq)
3 Cu(OH)2 (s) → CuO (s) + H2O (l)
4 CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O (l)
5 CuSO4 (aq) + Zn (s) → Cu (s) + ZnSO4 (aq)
Balanced reactions of the Copper Cycle
Results and Discussion: The Copper Cycle can be summarized as a series of reactions by the following balanced chemical equations:
Additionally, these equations are just quantitative descriptions of the different types of chemical reactions that occur as part of the Copper Cycle. These same reactions were assessed qualitatively for this experiment as …show more content…
Copper also gains a net charge of +2, so the reaction was a redox and also a gas-forming reaction. After the 4 mL of nitric acid was added to the .2511g of copper in the beaker, the copper metal effervesced and began to break down; eventually, it dissolved into solution as ions. A brown gas was observed forming in the beaker simultaneously as HNO3 is reduced and transformed to NO2, corresponding with the formation of nitrogen dioxide gas as the reaction progressed. The hydrated copper turned the water blue as the reaction was allowed to continue for about five minutes.
Step 2: precipitation
When sodium hydroxide (strong base) was reacted with copper(II) nitrate, the copper combined with the hydroxide ion to form an insoluble compound, copper hydroxide, making this a precipitation double displacement reaction. As the sodium hydroxide was added to the solution dropwise, the liquid changed color from blue-green-blue. The intensity of the color change grew as more of the copper(II) nitrate reacted to form a solid and the liquid reacted to form sodium nitrate – eventually the liquid was opaque and a layer of copper hydroxide settled at the bottom of the beaker.
Step 3:
Lynna Jezek*, Long Nguyen
CHEM 111-502
Introduction:
The element copper has proven to be of great use to human civilizations through time; from the first bronze smelted by the Sumerians to copper’s practicality in today’s industry-driven world, copper has become essential to human life. Copper’s use in industry (such as its great conductivity of heat and electricity) has driven many scientists to study the Copper Cycle, or how copper behaves as a response to different chemical environments. While oxidized copper ore is easily distinguished by its blue-green color, the complete Copper Cycle occurs with copper in both its elemental and oxidized states, which will be fully explored by sending copper metal through …show more content…
The solution was cooled, and 5 mL of distilled water was added to the beaker along with a magnetic stir bar for the final reaction. A mass of 528 mg of 20 mesh zinc was weighed out and added to the mixture; the solution was stirred for 15 minutes when it became colorless. Finally, the solution was decanted and 5 mL of 6 M HCl was added to complete the reactions of the Copper Cycle. The leftover solid was recovered using an aspirator, Büchner funnel, and distilled water to wash any remaining copper onto the funnel filter. The final mass of the copper metal was used to calculate the percent yield of copper in this series of reactions. Observations for each reaction step were recorded.
1 Cu (s) + 4HNO3 (aq) → Cu(NO3)2 (aq) + 2NO2 (g) + 2H2O (l)
2 Cu(NO3)2 (aq) + 2NaOH (aq) → Cu(OH)2 (s) + 2NaNO3 (aq)
3 Cu(OH)2 (s) → CuO (s) + H2O (l)
4 CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O (l)
5 CuSO4 (aq) + Zn (s) → Cu (s) + ZnSO4 (aq)
Balanced reactions of the Copper Cycle
Results and Discussion: The Copper Cycle can be summarized as a series of reactions by the following balanced chemical equations:
Additionally, these equations are just quantitative descriptions of the different types of chemical reactions that occur as part of the Copper Cycle. These same reactions were assessed qualitatively for this experiment as …show more content…
Copper also gains a net charge of +2, so the reaction was a redox and also a gas-forming reaction. After the 4 mL of nitric acid was added to the .2511g of copper in the beaker, the copper metal effervesced and began to break down; eventually, it dissolved into solution as ions. A brown gas was observed forming in the beaker simultaneously as HNO3 is reduced and transformed to NO2, corresponding with the formation of nitrogen dioxide gas as the reaction progressed. The hydrated copper turned the water blue as the reaction was allowed to continue for about five minutes.
Step 2: precipitation
When sodium hydroxide (strong base) was reacted with copper(II) nitrate, the copper combined with the hydroxide ion to form an insoluble compound, copper hydroxide, making this a precipitation double displacement reaction. As the sodium hydroxide was added to the solution dropwise, the liquid changed color from blue-green-blue. The intensity of the color change grew as more of the copper(II) nitrate reacted to form a solid and the liquid reacted to form sodium nitrate – eventually the liquid was opaque and a layer of copper hydroxide settled at the bottom of the beaker.
Step 3: