Question

In this laboratory exploration various reactions of copper will illustrate these properties. First, begin with copper...

In this laboratory exploration various reactions of copper will illustrate these properties. First, begin with copper metal. When concentrated nitric acid is added, dramatic changes occur and the metal dissolves forming a brightly colored copper ion-containing solution.

Cu(s) + 4HNO3(aq) à Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)                                       _____________ equation

Cu(s) + 4H+ + 4NO3-(aq) à Cu+2(aq) +2NO3-(aq)+ 2NO2(g) + 2H2O(l)                  _____________ equation

Reaction type_______________

What advantage(s) is/are there to the second version of the reaction equation?

However, if diluted nitric acid was used instead, the following reaction would have occurred:

3Cu(s) + 8HNO3(aq) à 3Cu(NO3)2(aq) + 2NO(g) + 4H2O(l)                                                        _____________ equation

3Cu(s) + 8H+ + 8NO3-(aq) à3Cu+2(aq) + 6NO3-(aq) + 2NO(g) + 4H2O(l)                 _____________ equation

Reaction type_______________

Why is the more caustic concentrated nitric acid used if both the concentrated and dilute acid solutions both produce the copper (II) ion, our desired result?

What are disadvantages of this method?    Safety concerns?

At this point, water is added to transform all the copper (II) ion into the water complex, forming a complex ion. This color change signals a Lewis acid/base reaction in which the water is the Lewis base and the metal ion is the Lewis acid. It also serves to dilute the acid, useful in the precipitation step to keep reaction temperatures down, and serves to disperse the gas formed.

Cu(NO3)2(aq) + 6H2O(l) à Cu(H2O)6+2(aq)   + 2NO3-(aq)                                             _____________ equation

Reaction type_______________

The next step in the copper atoms journey is the formation of copper (II) hydroxide when sodium hydroxide solution is added to the reaction mixture. This process must be done carefully, slowly and with a cool water bath, to prevent skipping this step and creating the copper (II) oxide product directly, the next step in the process, as well as redissolving the copper (II) hydroxide as a complex.

Cu(H2O)6+2(aq) + 2NaOH(aq)    à Cu(OH)2 (s)   + 6H2O(l) + 2Na+(aq)                       _____________ equation

Reaction type_______________

Adding excess hydroxide should be avoided as it results in redissolving the precipitate and forming a copper complex. Therefore the sodium hydroxide is added 1 drop at a time, mixed with the vortexer, briefly cooled in a cool water bath, and the reaction progress noted after each drop. Once the precipitate remains after mixing , 2 additional drops are added to ensure complete precipitation.

Why is complete precipitation necessary?

Once the copper (II) hydroxide precipitation reaction is completed , the reaction mixture is carefully centrifuged and the supernatant analyzed for complete precipitation.

How can it be determined that the reaction is complete?

Why was it necessary to add the sodium hydroxide dropwise and utilize a cool water bath?

What safety precautions are necessary for centrifuge use?

If complete precipitation has occurred, the supernatant is decanted and the remaining solid carefully heated (D) in a moderate Bunsen burner flame to transform it to the copper (II) oxide.

Cu(OH)2 (s) + D à CuO(s)   + H2O(l)  

What safety precautions are necessary for Bunsen burners?

When heating mixtures?

At this point, the CuO solid will be dissolved in preparation for the final recovery of copper metal. The CuO will be dissolved using the careful dropwise addition of acid (in this case 6M sulfuric acid) followed by vortexing (similarly to the copper (II) hydroxide precipitation earlier). All following processes may be done in either the hood or at the benches. In this step, avoiding addition of excess sulfate ion (a problem in the final step) is our goal. Although temperature control is not an issue during the dissolving process, a cool water bath will be necessary during the final reaction.             

CuO(s) + H2SO4(aq) à CuSO4(aq) + H2O(l)                                                   _____________ equation          

CuO(s) + 2H+ + SO4-2(aq) à Cu+2(aq) + SO4-2(aq) + H2O(l)                         _____________ equation

CuO(s) + 2H+(aq)   à Cu+2(aq) + H2O(l)                                                             _____________ equation

Reaction type_______________

What advantage(s) is/are there to the various versions of the reaction equation?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

In the final step, the copper metal is regenerated by reacting the copper (II) ion and magnesium metal.

Cu SO4(aq) + Mg(s) à Cu(s)+ MgSO4(aq)                                                                                                         _____________ equation

Cu+2(aq) + SO4-2(aq) + Mg(s) à Cu(s)+ SO4-2(aq) + Mg(aq)+2                    _____________ equation

Cu+2(aq) + Mg(s) à Cu(s)+ Mg+2(aq) )                                                             _____________ equation

Reaction type_______________

Using the species in the first equation, can any other products be predicted to form during the isolation of copper solid from solution?

What advantage(s) is/are there to the various versions of the reaction equation?

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

How can it be determined that the reaction is complete?

Once the reaction is complete, the centrifuge will be used to separate the copper metal formed from the reaction mixture. Once separated, the solid will be rinsed 3 times with deionized water , using the centrifuge to separate the solid from the rinse water after each rinse.

What is the purpose of the rinses?

There are multiple cautionary notes for this reaction. If excess sulfate is present in solution due to excess sulfuric acid being used to dissolve the copper (II) oxide, an additional solid will form, complicating the rinsing process and affecting yield.

What is the equation for this side reaction?

How will the yield be affected if the rinses are incomplete?

If the reaction mixture is allowed to get too warm another side reaction will occur, what is it?

If the cool water bath was not used, what would be the effect upon the copper metal yield? Why?

If magnesium is added once the copper ion reaction is complete, a further reaction of the metal will occur.

What is it?

After the final rinse, the copper metal is in the test tube.

How (experimentally) will the copper metal recovered % yield be determined?

0 0
Add a comment Improve this question Transcribed image text
Request Professional Answer

Request Answer!

We need at least 10 more requests to produce the answer.

0 / 10 have requested this problem solution

The more requests, the faster the answer.

Request! (Login Required)


All students who have requested the answer will be notified once they are available.
Know the answer?
Add Answer to:
In this laboratory exploration various reactions of copper will illustrate these properties. First, begin with copper...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Similar Homework Help Questions
  • .              CuO(s) + H2SO4(aq) à C...

    .              CuO(s) + H2SO4(aq) à CuSO4(aq) + H2O(l)                                                   _____________ equation           CuO(s) + 2H+ + SO4-2(aq) à Cu+2(aq) + SO4-2(aq) + H2O(l)                         _____________ equation CuO(s) + 2H+(aq)   à Cu+2(aq) + H2O(l)                                                             _____________ equation Reaction type_______________ What advantage(s) is/are there to the various versions of the reaction equation? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ In the final step, the copper metal is regenerated by reacting the copper (II) ion and magnesium metal. Cu SO4(aq) + Mg(s) à Cu(s)+ MgSO4(aq)                                                                                                         _____________ equation Cu+2(aq) + SO4-2(aq) +...

  • Reactions and Neutralization in the Copper Cycle A Cycle of Chemical Reactions of Copper PRE-LABORATORY ASSIGNMENT...

    Reactions and Neutralization in the Copper Cycle A Cycle of Chemical Reactions of Copper PRE-LABORATORY ASSIGNMENT Finish the pre-laboratory assignments before the laboratory experiment. Read the manual of this experiment and complete the following questions. 1. a. Identify oxidation-reduction reactions in the copper cycle experiment. For each oxidation-reduction reaction, write half reactions to show what is oxidized and what is reduced. Identify acid-base reactions and precipitation reactions in the copper cycle experi- ment. Write equations for the corresponding reactions. b....

  • Dissolution of Copper Metal Copper reacts readily with strong oxidizing agents (substances that readily remove electrons...

    Dissolution of Copper Metal Copper reacts readily with strong oxidizing agents (substances that readily remove electrons from other suhstances-i.e... Cu- Cu2 +2e). In this experiment, aqueous nitric acid, HNO, oxidizes copper metal to the copper(II) ion (opening photo): Cu(s) +4 HNO,(aq)Cu(NO)(aq) +2 NO (8) +2 H,0( .Cu HNO3 Cu(NO3)2 (28.1) CuSO The products of this reaction are copper(II) nitrate, Cu(NO)2 (a water-soluble salt that produces a blue solution), and nitrogen dioxide, NO2 (a dense, toxic, red-brown gas). The solution remains...

  • Copper start to finish lab questions 7a.) and 7b.) hopefully the last 2 images of information...

    Copper start to finish lab questions 7a.) and 7b.) hopefully the last 2 images of information help make the problem clearer 7. a) For each mole of Cu dissolved in the nitric acid solution (HNO3), how many moles of [Cu(H2O)612+ are formed? col were formed in your reaction? b) Given your data above, how many moles of [Cu(H2O)6]2+ Reaction I:Cu (s)+ 4 H3O (aq) +2 NO3 (aq) --> [Cu(H2O)]** (aq) +2 NO2 (g) The first reaction in the series is...

  • 1. Balance the three copper reactions: + H20 (1) Cu(NO3)2 (aq) + NO2(g) i) Cu (s)...

    1. Balance the three copper reactions: + H20 (1) Cu(NO3)2 (aq) + NO2(g) i) Cu (s) + HNO3 (aq) ii) Cu(NO3)2 (aq) + NaOH(aq) Cu(OH)2 (s) + NaNO3(aq) (aq) - iii) Cu(OH)2 (S) Cuo(s) + H2O (1) 2. In reaction (i), suppose you add 4.0 mL of 6 M nitric acid to a sphere of copper metal that weighs 0.65 grams. Which reactant is the limiting reagent? (Show your work)

  • 1. Balance the three copper reactions: +H20 (1) +NO2 (g) Cu(NO3)2 (aq) i) Cu (s) HNO3...

    1. Balance the three copper reactions: +H20 (1) +NO2 (g) Cu(NO3)2 (aq) i) Cu (s) HNO3 (aq) NANO3 (aq) NaOH (aq) Cu(OH)2 (s) + ii) Cu(NOs)2 (aq) + H2O (1I) CuO (s) iii) Cu(OH)2 (s) 2. In reaction (i), suppose you add 4.0 mL of 6M nitric acid to a sphere of copper metal that weighs 0.65 grams. Which reactant is the limiting reagent? (Show your work)

  • i only need g, h and I please Classifying Chemical Reactions continued Classifying Chemical Reactions continued...

    i only need g, h and I please Classifying Chemical Reactions continued Classifying Chemical Reactions continued 3. Write a balanced chemical equation for each reaction and classify the reaction. a. Copper metal heated with oxygen gives solid copper(II)oxide. 4 cu +02 → 2420 (5) combination reachon b. Mixing ammonium nitrate and sodium hydroxide solutions gives aqueous sodium nitrate, ammonia gas, and water. NHL NO2+ NaOH -> Na NO₃(aq) + NH₃ (9)+H₂O (e) double replacement c. Mercury(II) nitrate solution reacts with...

  • REACTION OF COPPER AND ITS COMPOUNDS PRE-LABORATORY QUESTIONS The following preparatory questions should be answered before...

    REACTION OF COPPER AND ITS COMPOUNDS PRE-LABORATORY QUESTIONS The following preparatory questions should be answered before coming to lab. They are intended to introduce you to several ideas that are important to aspects of the experiment. You must turn in your work to your instructor before you will be allowed to begin the experiment. 1. Balance the three copper reactions: Cu(NO3)2 (aq) + NO2(g) + H2O (1) i) Cu (s) + HNO3(aq) ii) Cu(NO3)2 (aq) + NaOH(aq) Cu(OH)2 (s) +...

  • Lawine six chemical equations describe the six reactions that you used to convert copper into compounds...

    Lawine six chemical equations describe the six reactions that you used to convert copper into compounds and ultimately reproduce the original copper sample. Consistent with the law of rvation of mass, determine if each of the given equations are balanced. Balance those that are unbalanced by including the appropriate coefficients. Reaction 1: Cu(s) + 4H*(aq) + 2NO;(aq) - Cu + (aq) + 2NO2(g) + H2O(l) Reaction 2: Cu?(aq) + OH(aq) - Cu(OH),(s) Reaction 3: Cu(OH),(s) - CuO(s) + 2H,0(1) Reaction...

  • there are reactions from 1 to 5. Q: what is %yield of Cu?, and % error?...

    there are reactions from 1 to 5. Q: what is %yield of Cu?, and % error? -reaction 1: 0.2134g of Cu, 2ml 6Mol HNO3 -reaction 5:0.1646g of Cu (solid) left. Balanced Equation reaction.1 Cu (s) + 4HNO3(aq) → Cu(NO3)2 (aq) + 2NO2 (g) + 2H2O (l) reaction 2: Cu(NO3)2 (aq) + 2NaOH (aq) → Cu(OH)2 (s) + 2NaNO3(aq) reaction 3: Cu(OH)2 (s) → CuO (s) + H2O (l) reaction 4: CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O(l)...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT