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Hello,

Here are some conceptquestions that come from a review for an exam, having some troubleplease help me!!! I know there are multiple questions, Sorry! Ihope someone will help me! be brief but I still want to be able toknow why its that answer! Thanks!

1. What is the purpose of the salt bridge in a galvanic cell? Couldyou have a galvanic cell without it?

2. If a redox reaction involves no net destruction or production ofelectrons, how do we obtain “half cell potentials?”

3. Is E0 positive or negative for an electrolytic cell? For agalvanic cell?

4. A battery is made of two half cells that have a combined E0 of1.8 volts. Is the voltage constant through the life of the battery?Explain why or why not.

5. A galvanic cell is made from a Zn rod in a solution of 1.0 MZnSO4 and a Cu rod in a solution of 1.0 M CuSO4¬. The two cells areconnected with a salt bridge and used to run a small motor. What isthe voltage produced from this cell and which electrodes getsheavier (due to plating of metal) and which electrodes becomeslighter via corrosion. Which electrode is the anode, which is thecathode? You can assume that both half cell reactions involve 2e-.

6. What is the voltage of the cell above if instead, a 0.10 Msolution of ZnSO4 is used? What is the voltage when equilibrium isreached?

7. Using the galvanic system in #7 above, show what happens to thecell voltage as the battery is used. Show what happens withchemical equations and calculate the voltage with the Nernstequation.

8. Explain in detail one of the commercially electrochemicalprocesses described in class. Show the redox equations, explain thetype of electrochem process and explain why this process isindustrially important.



I hope you can HELP!Thanks!

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Patrina Schowalter
Patrina SchowalterLv2
28 Sep 2019

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Related questions

Hello,

Here are some conceptquestions that come from a review for an exam, having some troubleplease help me!!! I know there are multiple questions, Sorry! Ihope someone will help me! be brief but I still want to be able toknow why its that answer! Thanks!

1. What is the purpose of the salt bridge in a galvanic cell? Couldyou have a galvanic cell without it?

2. If a redox reaction involves no net destruction or production ofelectrons, how do we obtain “half cell potentials?”

3. Is E0 positive or negative for an electrolytic cell? For agalvanic cell?

4. A battery is made of two half cells that have a combined E0 of1.8 volts. Is the voltage constant through the life of the battery?Explain why or why not.

5. A galvanic cell is made from a Zn rod in a solution of 1.0 MZnSO4 and a Cu rod in a solution of 1.0 M CuSO4¬. The two cells areconnected with a salt bridge and used to run a small motor. What isthe voltage produced from this cell and which electrodes getsheavier (due to plating of metal) and which electrodes becomeslighter via corrosion. Which electrode is the anode, which is thecathode? You can assume that both half cell reactions involve 2e-.

6. What is the voltage of the cell above if instead, a 0.10 Msolution of ZnSO4 is used? What is the voltage when equilibrium isreached?

7. Using the galvanic system in #7 above, show what happens to thecell voltage as the battery is used. Show what happens withchemical equations and calculate the voltage with the Nernstequation.

8. Explain in detail one of the commercially electrochemicalprocesses described in class. Show the redox equations, explain thetype of electrochem process and explain why this process isindustrially important.



I hope you can HELP!Thanks!

1. (1 point) What are transferred in an oxidation-reduction reaction? *

• atoms

• electrons

• ions

• protons

2. (1 point) In the reaction of beryllium with fluorine, which atom is oxidized? *

• fluorine

• beryllium

• neither of them

• both of them

3. (1 point) Ag - - > Ag ^+ +1 e^- This equation represents the type of reaction called _____. *

• hydrolysis

• oxidation

• redox

• reduction

4. (1 point) What is the reducing agent in the following reaction? 2K + S - - > K2S *

• K

• S

• K2S

• None of the above

5. (1 point) The oxidation number of oxygen when it is in a compound other than a peroxide is ____. *

• -2

• -1

• 0

• +2

6. (1 point) What is the oxidation number for each atom in NH4F? *

• N=+3, H=-4, F=+1

• N=-3, H=+1, F=-1

• N=+3, H+1, F=-1

• N=-3, H=-1, F=+1

7. (1 point) Which atom has a change in oxidation number of +4 in the following redox reaction?K2Cr2O7 + H2O + S - - > KOH + Cr2O3 + SO2 *

• K

• Cr

• O

• S

Metal activity series for question 8

8. (1 point) Of the following metals, which ions are most easily reduced? Use the above table to answer the question. *

• magnesium

• lead

• copper

• sodium

9. (1 point) In a zinc-copper cell, Zn(s) | Zn^+2(1M) || Cu^+2(1M) | Cu(s), which electrode is positive? *

• Cu^+2

• Cu(s)

• Zn(s)

• Zn^+2

10. (1 point) How must a redox reaction that is to be used as a source of electrical energy be set up? *

• One half reaction must involve two metals.

• Two half reactions must use a metal wire electrodes.

• One half reactions must involve more than one electron.

• Two half reactions must be physically separated.

11. (1 point) In a voltaic cell at which electrode does reduction occur? *

• anode only

• cathode only

• both anode and cathode

• Either anode or cathode , depending on the metal

12. (1 point) What assures that there is no charge build up in a voltaic cell as oxidation and reduction occur? *

• one of the half cells

• the electrolyte solutions

• the moving electrons

• the salt bridge

13. (1 point) In the most common dry cell what material is the electrode that is the center rod made of? *

• copper

• graphite

• lead

• zinc

14. (1 point) To charge a lead storage battery you must ________. *

• apply a direct current to it.

• hold a magnet close to it.

• Use alternating current through it.

• increase the oxygen in it.

15. (1 point) In a hydrogen- oxygen fuel cell ______________. *

• hydrogen diffuses through the cathode.

• hydrogen and oxygen are mixed before entering the anode.

• oxygen diffuses through the anode.

• oxygen diffuses through the cathode.

16. (1 point) When electrical energy is used to cause a chemical reaction we call this process _____. *

• electronation

• electrolysis

• hydration

• reduction

17. (1 point) Which of the following is true about an electrolytic cell? *

• It changes chemical energy into electrical energy.

• It is the type of cell used in electrocution

• It uses an electric current to make a nonspontaneous reaction go.

• All of the above

18. (1 point) The products formed in the net reaction of the electrolysis of water are ____. *

• aqueous hydrogen ion and hydroxyl ion

• hydrogen gas and oxygen gas

• hydrogen gas and liquid oxygen

• water vapor

19. (1 point) What occurs in electroplating? *

• decomposition of an ionic compound

• decomposition of a salt layer

• deposition of a metal layer on a material

• deposition of a salt layer on a metal

Open response Questions : Answer questions 20 through 22 in complete sentences

20. ( 5 points) Write the equation for the reaction of calcium and oxygen ( 1 point). Write the oxidation numbers for both the reactants and the products ( 2 points) What is the reducing agent and why? ( 2 points)

21. ( 5 points) Tell how a voltaic cell works. Be sure to mention the various parts of the voltaic cell and what they have to do with how it works.

22. (4 points) What are the signs given to the electrodes in both the voltaic and electrolytic cells? What reaction (oxidation or reduction) is occurring at each?

I'm working on a project I need some help with (BTW I asked my teacher and I am allowed to ask for help). If there was anything I wasn't clear on please tell me because I'm just hopelessly lost on this. Also just to note this actually has a fair bit of chemistry in it but because it's all related to electricity and there is no chemistal engineering subject Tab I put it here.

Okay so in this project we have a hypothetical scenario. In this scenario I'm on an abandoned island and I need to power a satellite for 97 minutes at 12 volts at 30 amps and 5 volts at 45 amps. But on this island are various supplies including a 1987 V8 engine which I think will provide 12 volts at 30 amps. Now what I need is fuel to get it going. I have 4 deep friers full of oil, 3 cases of magnum bottles of champagne, salt water from the ocean, 21 2 gallon jars of pickled eggs, and 33-5 gallon containers of italian salad dressing, and 23 #10 cans of tomato sauce. There is also an abandoned moonshine still. So using the oil from the friers, the champagne, and getting the oil out of the salad dressing I should be able to get a decent amount of biofuel correct? I also have 9 full 20# propane tanks and I read that propane can be used to make fuel burn more efficiently by taking the place of the air injection. If there anything else from this list that I could make into fuel of some kind? What about Moonshine everything I read mentions sugar and yeast which I don't think I have either of.

So assuming I have that all worked out okay that gets me my 12 volts at 30 amps. But I still need the 5 volts at 45 amps. And one solution I was thinking of was making voltic cells. Amoung the materials I have to work with that are of use here are some 1/2'' and 3/4'' copper pipes, 8 roles of aluminum foil, 23 20ft lengths of 6 in. sch. 40 PVC pipe, 17 20ft lengths of 4in. sch. 40 PVC pipe, and 9 20ft lengths of 2 in. Sch. 40 PVC pipe. I also have some cans of cold galvanizing spray paint ( meaning I have zinc), and various containers including a lot of PVC pipe, 55 gallon plastic drums, and a complete set of commercial pots and pans. I also have various wires but I'll put that asside for now. I also have access to some PH adjust (down)

Now what I want to do is make a battery set up that can deliver 5 volts at 45 amps for 97 minutes.

I know I can make several battery cells and connect them in series and parallel to get the desires voltage and current. But i'm having trouble figuring out what my voltage and amperage would be for each cell. Also how long would the charge last?

I read something called aluminum-air batteries but I'm not clear on how they are made or if they are ideal for what I need. Would using the pickling solution from the pickled eggs as my electrolyte be better than using the salt water? Or should I separate the vinegar out of the salad dressing and us that? Would using the PH adjust (down) help?

I tried looking up some reduction charts but those were all in aqueous. What I was able to get was that for copper and aluminum it was about 2 v potential and for copper Zinc it was about 1.01 v. Is this correct? For a base line lets say I just use the PVC pips, copper pipe, aluminum foil, Salt water, and for wiring I use copper wire. if I"m correct and I get about 2 V from each battery how do I find my amperage? What part of all this affects the current and how would I calculate it? Would using a different kind of wire be better? I have access to a couple different kinds.

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