Chem Lab Exam 1: Reactions Of Copper

Front 1

What is the purpose of this lab?

Back 1

To purify a sample of copper via a number of different types of reactions.

Front 2

Name the different types of reactions that will occur during the experiment

Back 2

Redox, acid-base, precipitation

Front 3

Explain the steps and write the corresponding chemical equation for reaction 1. What kind of reaction is this?

Back 3

First, cut pieces of copper wool and put into a beaker, Recording the exact mass of the copper. Add nitric acid (HNO3). This creates copper nitrate (CuNO3)2 and a brown gas of nitrogen dioxide (NO2). Once no more gas has been released, add about 50 mL of deionized water (H2O) to the beaker.

--Copper metal (s) + nitric acid --> copper (II) nitrate (aq) + nitrogen dioxide gas (g) + water (l)
--Cu(s)+4HNO3(aq) --> Cu(NO3)2(aq)+2No2(g)+2H2O(l)

- This is a redox reaction

Front 4

Explain the steps and write the corresponding chemical equation for reaction two. . What kind of reaction is this?

Back 4

The beaker now contains copper nitrate Cu(NO3)2. add 20 mL of sodium hydroxide (NaOH) to neutralize and precipitate copper hydroxide Cu(OH)2, which will appear a fluffy bluish white solid. Sodium nitrate (NaNO3) was also yielded from the reaction.

Copper (II) Nitrate (aq) + Sodium hydroxide --> copper hydroxide + sodium nitrate

-Redox

Cu(NO3)2+NaOH--> Cu(OH)2(s)+2NaNO3(aq).

Front 5

Explain the steps and write down the corresponding chemical reaction for reaction three. What kind of reaction is this?

Back 5

Now, stir gently with a magnetic stirrir, and use a thermometer to heat the mixture to 60°C on a hot plate, making sure not to boil the solution. The heat from this process will dehydrate the gelatinous copper hydroxide Cu(OH)2 form Black flakes of copper oxide, CuO. Wow the copper oxide is settling, warm and a 600 mL beaker full of distilled water to about 60°C. when the black copper oxide has completely settled, decant. Use the warm water (H2O) to perform many washes of the copper oxide CuO.

Copper hydroxide --> copper oxide + water

Cu(OH)2(s)-->CuO(s)+H2O(l)

This is a decomposition reaction

Front 6

Explain the steps and write down the corresponding chemical reaction for reaction four. What kind of reaction is this?

Back 6

After the washing and decantation of the copper oxide, at about 8 mL of sulfuric acid H2SO4 to dissolve the copper oxide. Stir the solution until it becomes clear blue. Copper (II) sulfate CuSO4 and water H20 are formed.

-- copper oxide + sulfuric acid --> copper (II) sulfate + water

-- CuO (s) + H2SO4 --> CuSO4 (aq) + H2O (l)

-this is a metaphysis reaction

Front 7

Explain the steps and write down the corresponding chemical reaction for reaction five. What kind of reaction is this?

Back 7

At this point, you now have copper (II) sulfate CuSO4 and water. Weigh out approximately 2 g of zinc metal and added it in very small portions as needed, to recover the Copper metal. Aqueous Zinc sulfate (ZnSO4) it's also yielded from the reaction. Occasionally swirl the solution until it colorless. Then, decant the remaining supernactant (ZnSO4). Now that we have restored the Copper metal, we need to get rid of the remaining zinc. Go to the exhaust vent and add about 3 mL of distilled water and stir. Then, carefully add about 5 mL of HCl to oxidize any remaining zinc. The small amount of gas (H2) Will be released, leaving the remainder of zinc chloride ZnCl2, which will be decanted.

Copper (II) Sulfate + Zinc metal --> Copper metal + aqueous Zinc Sulfide

--> Zinc + HCl --> aqueous Zinc Chloride + Hydrogen gas

- CuSO4 (aq) + Zn (s) --> Cu (s) + ZnSO4 (aq)
-- Zn + HCl --> ZnCl2 (aq) + H2 (g)

Front 8

Upon completion of reaction five, what do you do with the restored copper to finish the experiment?

Back 8

After the copper has been restored, wash the copper with distilled water several times, and then watch the copper with isopropyl alcohol at least three times. On the final washing, transfer the copper into an evaporating dish and decant remaining isopropyl alcohol. Then, transfer the copper into the different pre-weighed evaporating dish. Warm the evaporating dish on a hotplate (Warm to the touch). Too much heat will cause a oxidation back to copper oxide, which would be irreversible. Two little heat will cause the sample to retain isopropyl alcohol, both scenarios resulting in a high recovery error. After cooling, reweigh the evaporating dish and recovered copper until the final mass of copper is below and within .004g of the lowest mass previously recorded.

Front 9

When you are heating the newly restored copper on the hot plate to evaporate the remaining isopropyl alcohol, what do you risk happening if the heat is too high? What if it is too low?

Back 9

If is too high, the copper will oxidize back to copper oxide, which is irreversible. To Llover temperature will cause the isopropyl alcohol to remain in the Copper. Both scenarios would cause an exceedingly high percent recovery.

Front 10

Write a complete, balanced chemical equation for the following reaction:

Aqueous lead (II) chloride reacts with aqueous potassium carbonate

Back 10

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Front 11

Write a complete, balanced chemical equation for the following reaction:
Solid nickel reacts with aqueous copper (II) chloride.

Back 11

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Front 12

Write a complete, balanced chemical equation for the following reaction:
Aqueous sodium carbonate reacts with aqueous hydrobromic acid.

Back 12

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Front 13

Write a complete, balanced chemical equation for when tin metal reacts with aqueous HCl to produce tin (II) chloride and hydrogen gas.

In this reaction, which element is oxidized, and which element is reduced?

Back 13

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Front 14

Write the reaction for when Copper reacts with Nitric Acid.

Back 14

Cu(s)+4HNO3(aq)-->Cu(NO3)2(aq)+2NO2(g)+2H2O(l)

Front 15

Write the reaction for when Copper II Nitrate reacts with Sodium Hydroxide.

Back 15

Cu(NO3)2(aq)+NaOH(aq)--> Cu(OH)2(s)+2NaNO3(aq)

Front 16

Write the reaction for when Copper Hydroxide reacts with heat

Back 16

Cu(OH)2(s) + heat --> CuO (s) + H2O(l)

Front 17

Write the reaction for when Copper Oxide reacts with Sulfuric Acid.

Back 17

CuO(s)+H2SO4(aq) --> CuSO4(aq) + H20 (l)

Front 18

Write the reaction for when Copper Sulfate reacts with Zinc metal.

Back 18

CuSO4(s)+Zn (s) --> Cu (s) + ZnSO4 (aq)

Front 19

Write the reaction when Zinc reacts with Hydrochloric acid.

Back 19

Zn (s) + HCl (aq) --> ZnCl2 (aq) + H2