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  Q1 : Week 4 – 9/25 – 9/29

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Please Make sure Your read all instructions for all assignments.    

LAB 1 – Gerber Voltaic Cell is LATE!!!!!  

LAB 2 – Voltaic Cell design is due Tuesday 9/26

  ____________________________________________                                                                                                                                                       9/25 – Monday – Yom Kippur  – 

                                                                         

                                                                                                                                                                     

                                                                                                                                                                                                                                       Jump toTuesday Homework / top
______________________________________________________________________________
9/26 – Tuesday – B Day – 2/3b Lab, 4 

Main focus    

a) To Review the concepts of the electrolytic cell with an electroplating demo and electrolysis demo.

b) To take Notes on the 2 types of Electrolytic Cells.      

Period 2,4:

1) One last battery demo – does it have to be fancy??
 
2) Electrolytic Cell- Electrolytic cell Demo of electrolysis of KI (aq)
                                   Electroplating demo 
 
– Took notes on worksheet for the 2 demos.
 
Intro Electrolytic Cells Demo worksheet.pdf
                                                                                                                                                                                                  weekend homework:                                                                                                                                       Intro Electrolytic Cells worksheet 1 Key.pdf

View Download

Period 3b:

1) Setup the Electrolysis of copper (II) chloride lab – 

2) Michael Faraday and his experimental finding with electrolytic cells:

 Faraday’s laws of electrolysis that *basically states:
 
1: The mass of the deposited metal is directly proportional to the quantity of electrical charge that passes through the electrolyte.
 
2: For the same quantity of electricity or charge passes through different electrolytes, the mass of the deposited chemical is directly proportional to its chemical equivalent and inversely proportional to its valency.

_______________________________________________________________________                                                                                                            Lab 3 – Electrolysis of copper (II) chloride
 

 LAB  3  – Determine the grams of copper collected at the cathode of an electrolytic cell of an unknown concentration of copper (II) chloride– 

a) Setup an electrolytic cell                                                                                                                        b)complete the lab diagram                                                                                                                                  c) collect and filter your copper                                                                                                                            d) place in the oven 

 
Lab 3 – Electrolysis of CuCl2.pdf

Electroplating Demo For Today’s Notes 

Electroplating Demo For Today’s Notes

Today’s Lesson:

 ______________________________________________________                                                                          Jump to top                                    9/19 – Tuesday Homework: –

1.  Complete Stoichiometry 8 redox electrolytic – 1999.pdf worksheet SIDE 1 One ONLY with
        the lecture below that reviews question below!
 
      Please complete side 1 of this worksheet the following ways:
 
         a) You need to be able to draw and label the electrolytic cell that the question describes just like you                    did from the diagram of the demo’s today.  3 hints below will help!
 
        * Please remember that you are heating the AlCl3 (s) until the ions are free.  Based on the chemical              formula you should be able to figure out what ions are present.  Also this goal of the electrolytic cell is make the elemental form of each ion.  We are looking to make pure Al  and Chlorine gas (Cl2).
 
         *Remember that you will include a battery (batt) in your diagram and depending  where you draw the anode/cathode of the Battery (voltaic cell) and how you connect it to the electrodes (that do not react) in the electrolytic cell will determine which  electrode is the anode/cathode in the electrolytic cell. There are many correct ways to diagram this.
 
         *But the ions will move only to the correct electrode based on their charges!
 
          b) The second part, determining how many grams was deposited on the cathode is tonight’s  
               stretch. Please read the Notes on Electrolytic Cell below.
 
          c) Try making the calculation using the notes, the key, or the lecture.  I suggest that you try it  
               after reading the notes and then view my lecture below to see how I did the question.
                You could use the key below or just let me walk you through the problem. 
 
Do not worry about the calculation in the second part if it gives you trouble. I will go over and reteach that in class tomorrow.                                                                                                                                                                                                    
Stoichiometry 8 redox electrolytic – 1999.pdf
 
Stoichiometry 8 redox electrolytic KEY – 1999.pdf
View Download

   

NOTES on the Electrolytic cells:
These electrolytic problems are centered around a couple of concepts:
 
1. Coulomb = SI unit of charge
2. Faraday’s Constant
 
If the current in a circuit is 1 Ampere then 1 coulomb of charge passes a point in the circuit every second.
 
1.0 A = 1  C/sec   (1 Amp = 1 Coulomb per second)
 
Abbreviation:  C as in Amperes above
Equation symbol: q or Q (as in Coulombs Law)
 
q = -1.60 x 10-19 C in a single electron (the charge in a single electron = -1.60 x 10-19 C )
 
There are also 1.60 x 1018 electrons in 1 Coulomb
 
We use the concept of Coulomb to connect Amperes which measures current (or measure amount of the flow of electrons) that is being pushed through the conductor (or wire) by a voltage (Energy). A measures amperage over a measures amount of time will give us the AMOUNT OF CHARGE that passes over a point in the wire IN THAT TIME INTERVAL.
 
So Amperage (A = C/sec ) describes TOTAL CHARGE IN A TIME INTERVAL!  So the key is the TIME and  measured Amperage will give us total charge.
 
Now once we have TOTAL CHARGE we can relate Faraday’s Constant which came from Faraday’s laws of electrolysis that *basically states:
 
1: The mass of the deposited metal is directly proportional to the quantity of electrical charge that passes through the electrolyte.
 
2: For the same quantity of electricity or charge passes through different electrolytes, the mass of the deposited chemical is directly proportional to its chemical equivalent and inversely proportional to its valency.
 
Now at the time of Michael Faraday there was very little support for the idea of atoms , atomic or moles.  Just chemical properties. One property that was well know was the valency of elements.  Copper has a valency 2 because they knew 2 Cl ions would bind with Cu.  This valency of course is valence electrons and is related to the 
ELECTRONS IN THE HALF REACTION!!!!
 
                                                                                 Cu+2 + 2e —->   Cu (s)
 
There was no understanding of mole concept yet so Faraday could not relate these observations in an electrolytic cell to moles.  Once the mole equivalent was determined in the turn of the Century (1905) could a constant be described that relates charge of electrons with a mole of electrons.  Faraday set the stage and the mole concept closed the door.  Faraday would dance aggressively happy is he saw what we can predict with this constant given in his name:
 

                                   F (Fancy) = 96,500 C / 1 mole of electrons

 
SO we can Now link the Total charge we get from measures Amperes and Time to the Quantity of electrons that are being forced through conductor. Since these electrons are being used at each electrode to “Force” an non-spontaneous reaction we can use the ratio of electrons that are responsible for the Coulombs to determine the number of atoms that are being produced at either electrode.  
 
In the case of Copper above there are 2e per 1 Cu+2 in the half reaction above so 
if there will be twice as many electrons needed as Cu atoms deposited.  
 
Faraday’s constant the total charge (we get from Amperage and time) to total number of electrons in half reactions occurring at the electrodes. Using the ration of electrons to atoms produced in the half reaction we can determine the amount of atoms.                                                                                                                                                
Example:  How many grams of Cu are deposited on the cathode in an electrolytic cell if the cell runs for 90 minutes at an amperage of 3.0 A?
 

                          

Tonights lecture for the Stoichiometry 8 redox worksheet For Homework! 

End of Tuesday!

                                                                                                                                                                                                                                Jump toWednesday Homework / top ______________________________________________                                                                                             9/27 – Wednesday – A Day – 2/3a Lab, 4 

Main focus 

a) To connect Faraday’s early work with our new stoichiometric calculation that determines the amount of metal plated at the cathode.                                                                       

b) To discuss the use of units in dimensional analysis.        

     
c) To calculate the amount of grams of metal that is plated at the cathode of an electrolytic cell.
     
Period 2,4:
    

1.  Discussed Faraday’s work and what was discovered in his electrolysis experiments

a) Used notes posted under the homework:

1791 – 1867 – Micheal FaradayAlbert Einstein’s man crush

-coined the terms anode, cathode, electrodes
– discovered electromagnetic induction among many other concepts in physics and chemistry
 
Faraday’s laws of electrolysis that *basically states:
 
1: The mass of the deposited metal is directly proportional to the quantity of electrical charge that passes through the electrolyte.
 
2: For the same quantity of electricity or charge passes through different electrolytes, the mass of the deposited chemical is directly proportional to its chemical equivalent and inversely proportional to its valency.

 

2.  Modeled the Electrolytic Practice Problems ( I used this new worksheet to teach calculations instead of using the backside of the homework. I will revisit that in analytic chemistry)

Electrolytic Practice Problems.pdf                                                                                                  View Download

– Voltage vs Amperage

a) Coulombs = amount of charge due to electrons

– Chemical equivalents = mole concept –> relative atomic masses

a) grams to moles

 
Stoichiometry 8 redox electrolytic – 1999.pdf
 
Stoichiometry 8 redox electrolytic KEY – 1999.pdf
View Download
   

 

Period 3a :

1) Setup the Electrolysis of copper (II) chloride lab – 

_______________________________________________________________________                                                                                                            Lab 3 – Electrolysis of copper (II) chloride
 

 LAB  3  – Determine the grams of copper collected at the cathode of an electrolytic cell of an unknown concentration of copper (II) chloride– 

a) Setup an electrolytic cell                                                                                                                        b)complete the lab diagram                                                                                                                                  c) collect and filter your copper                                                                                                                            d) place in the oven 

 
Lab 3 – Electrolysis of CuCl2.pdf

Today’s lesson : Actual Faraday’s findings into electrolytic calculations.

______________________________________________                                                                                              Jump to top                  9/27 – Wednesday Homework: –

                                                                                                  

1. Please view the lecture below and follow along with me to complete the                                                     

Lecture on Electrolytic cell – Molarity calculations worksheet:                                                                         These are the calculations that I use to setup the next lab.

Electrolytic cell – Molarity calculations .pdf
View Download                                                                                                                                                                                              
Electrolytic cell – Molarity calculations Key p .pdf
View Download

                                                                       

2. Please Complete Intro Electrolytic Cells worksheet 2.pdf worksheet and review with key below:

 This worksheet is an example of a Past AP problem* that is asking for the students to solve for the Molarity or the concentration of a initial concentration in an electrolytic cell. IT is based on the Lecture above. 
 
                                      It is a great example of how you have to understand the material.
 
This question is using a voltaic cell with Amperage type questions that usually are seen with electrolytic cells.  
*The key to this worksheet is identifying that the electrochemical cell chemical reactions are for a voltaic cell and that its setup is a little different than we have seen, except in Lab 2.  The solutions will not always contain the ions of the metal electrode AND sometimes as in this case in this problem the oxidation occurs from the solution and not the Anode.  They did not provide a diagram, but if you could envision 2 platinum electrodes in the 2 solutions in separate cells with some sort of a salt bridge then you are Gucci.
 
*Also when they state, ” at which point the C2H5OH (aq) has been totally consumed” just means when all of the C2H5OH (aq) has oxidized and the reaction stops.  How much Amperage (flow of electrons) was needed to run the oxidation half cell empty?
   
Intro Electrolytic Cells worksheet 2.pdf
View Download
 
Intro Electrolytic Cells worksheet 2 key p.pdf
View Download
 
       
                            

1: Lecture on Electrolytic cell – Molarity calculations worksheet

                                                                                                                                                                                                                        Jump to:  Thursday Homework / top
__________________________________________________________                                                                                                                                       9/28 – Thursday – B Day – 2, 3b/4 Lab 

Main focus 
       
a) To Review Electrolytic cell calculations from Homework. Specifically the use of                      Faraday’s constant and amperage.                                                                                                                                                                        

b) Perform an electrolytic cell Lab by determining the mass of Cu at the cathode.      

  
Period 2:
 
1. Continue with yesterday’s lab
   
    a) heat and wash copper off the electrodes.
    b) Perform a hot filtration (after measuring the mass of the filter paper)
    c) place filter paper on a watch glass and place in oven
    We will obtain the experimental mass when the copper is dried. 
    d)  Calculate the theoretical amount of copper (expected Friday when copper is dried)  

 
2. Review the Homework: 
                                                                 
     Electrolytic cell – Molarity calculations Key p .pdf

      View Download

      Intro Electrolytic Cells worksheet 2 key p.pdf
      View Download                                                                                                                                                            

Period 3b/4:

1. Perform the electrolytic cell lab again for 30 minutes (sorry I thought is would be best to do it all from the beginning)
    a) heat and wash copper off the electrodes.
    b) Perform a hot filtration (after measuring the mass of the filter paper)
    c) place filter paper on a watch glass and place in oven
    We will obtain the experimental mass when the copper is dried. 
    d)  Calculate the theoretical amount of copper (expected Friday when copper is dried)  
 
2. Review the Homework: 


3. Complete the classwork(back side of the previous homework worksheet)   

     
    Stoichiometry 8 redox electrolytic – 1999.pdf
 
     Stoichiometry 8 redox electrolytic KEY – 1999.pdf
    View Download

                                                                                                                    

_______________________________________________________________________                                                                                                            Lab 3 – Electrolysis of copper (II) chloride
 

 LAB  3  – Determine the grams of copper collected at the cathode of an electrolytic cell of an unknown concentration of copper (II) chloride– 

a) Setup an electrolytic cell                                                                                                                        b)complete the lab diagram                                                                                                                                  c) collect and filter your copper                                                                                                                            d) place in the oven                                                                                                                                            e) Calculate the theoretical amount of grams of copper expected.

 
Lab 3 – Electrolysis of CuCl2.pdf

____________________________________________________                                                                              Jump to top                  9/21 – Thursday Homework: –

1. Please view the Electrolysis of water demo to understand how water can be oxidized and 
    reduced in water:                                                                                                                                                                                                                       
2. Complete and review the following worksheet with the key and/or Video below:
 
Electrolytic Problems Expanded.pdf
View Download
 
Electrolytic Problems Expanded key p.pdf
View Download
 
 3. Start reviewing your electrolytic cell worksheets.  A quiz is coming soon!

 

Electrolysis of water review video

Electrolytic Problems Expanded Review video: 

 

                                                                                                                                                 Jump toFriday Homework/top         __________________________________________________________________                                                                                                           9/29 – Friday – A Day – 2/3a Lab, 4  

Main focus 

a) To experimentally determine the mass of copper deposited at the cathode of an electrolytic cell from an aqueous solution of copper (II) Chloride.

b) To calculate the theoretical mass of copper that would be expected

c) To determine how the electrolysis of water affects the results of the Lab.

Period 2,4:

1.  View the Electrolysis of water demo – fuel cells

       a) water get oxidized

       b) water gets reduced

2.  Review of Wednesday’s Homework – Molarity – Voltaic cell with electrolytic calculations

Intro Electrolytic Cells worksheet 2.pdf
View Download
 
Intro Electrolytic Cells worksheet 2 key p.pdf
View Download
 
 
 
3.  Review of Thursday’s Homeworkcombining Voltaic cell with electrolytic cells and calculations
 
Electrolytic Problems Expanded.pdf
View Download
 
Electrolytic Problems Expanded key p.pdf
View Download
 
Period 3a:
 

1.  Mass out filter paper with copper that was in the oven overnight

2.  subtract out filter paper.

3.  Determine the experimental mass of copper.

4.  Calculate percent error and calculate the molarity of the solution  

 

Electrolysis of water demo today

_______________________________________________________________________                                                                                                            Lab 3 – Electrolysis of copper (II) chloride
 

 LAB  3  – Determine the grams of copper collected at the cathode of an electrolytic cell of an unknown concentration of copper (II) chloride– 

a) Setup an electrolytic cell                                                                                                                        b)complete the lab diagram                                                                                                                                  c) collect and filter your copper                                                                                                                            d) place in the oven                                                                                                                                            e) Calculate the theoretical amount of grams of copper expected.                                                                          f) Determine experimental mass of copper.                                                                                                          g) Calculate percent error and Molarity of solution.

 
Lab 3 – Electrolysis of CuCl2.pdf

__________________________________________________                                                                    Jump to top                                          9/29 – Friday’s Homework: –

1.  We will have a quiz that will encompass both the voltaic and electrolytic cell on next Monday, 10/2.
 
 I would go back and review all worksheets, keys, and videos that I posted on electrolytic cells.  In the mean time I am assigning an Extra Credit Form for the weekend that is DUE BY Monday,   I will return your graded submission and will post the key below the form.  I will review in class Monday!
 
This extra credit Form will provide EXTRA POINTS for the quiz on Monday. There will be no makeup to this quiz.  It is time to start putting this together and asking directed questions on points you do not understand. If you are sitting back and being pedestrian in this process it will not work for you. THIS EXTRA CREDIT ASSIGNMENT is very much like the quiz you will see Monday!
 
    Please use the following worksheet posted for the EXTRA Credit form posted below:                                                               
Electrolytic cell quiz extra Credit Form 1819.pdf
View Download

About the Microbial Electrolytic Cell in the Form below:
Natural gas has a dominant role in our energy supply. However, most of our natural gas is of fossil origin and therefore it is of utmost importance to have a renewable source of natural gas. Currently, the only renewable alternative to natural gas of fossil origin is to produce natural gas from biomass, e.g. organic waste, and crops. This alternative is of limited use, however, as land, water, and fertilizer, needed to produce the required biomass, are scarce and its use may not compete with food production. Here we propose a new technology that is capable of converting (excess) electricity and CO2 into methane (CH4), the main component of natural gas. 
 
The points given back on the the electrolytic cell quiz will be determined by the following:
 
 Raw score 13 12 11 10 9 8 7 6 5 4
*Bonus Points 10 9 8 7 6 5 4 3 2 1
*So you need to get at least 4 correct answers (out of 13) to get 1 Bonus Point.  If you got 13/13 you earned the max point = 10 points.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          

 
Extra Credit Form:  IT IS NOT ON AUTO-REPLY –  You have one submission for this form and I will grade and send you your answers over the weekend.  The form is due by SUNDAY AT 4:00 pm.  I will sent out emails of your results of your submission after 4:00 pm Sunday and will post the key below the form.  

 

THIS FORM IS NOW CLOSED! 

 

End of week 4!

Electrolytic Extra Credit Form Review : Posted ….

Please review your form with the following key. I will review in class.  WE WILL HAVE AN ELECTROLYTIC CELL QUIZ Monday.  I Want to review this quiz, finish the lab, and review molarity in class first.

Electrolytic cell quiz extra Credit Form KEY 1819.pdf
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