Archive – week 2- 20 -21
Week of 9/14 – 9/18
The 4 day – A, B, C, D cycle looks like this: And Monday starts on an A day!
Day Period
2 3 4
In class: A Lab Lab Single Class
Remote: Lab Lab Single Class
In class: B Single Class LAB LAB
Remote: Single Class LAB LAB
In class: C Single Class LAB LAB
Remote: Single Class LAB LAB
In class: D Lab Lab Single Class
Remote: Lab Lab Single Class
This week’s 5 day Schedule:
9/14 – Monday “A” Day – period 2,3 (Lab) – I 2(A,C) 3(A) AP CHEMISTRY
–period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – I 3(C) 4(A,C) AP CHEMISTRY
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
9/15 – Tuesday – “B” Day –period 2, – I 2(B,D) 3(D) AP CHEMISTRY
– period 2, – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 3,4 (LAB) – I 3(B) 4(B,D) AP CHEMISTRY
-period 3,4 (LAB) – R 3(B) 4(B,D) REMOTE INSTRUCTION
9/16 – Wednesday “C” Day – period 2, – I 2(A,C) 3(A) AP CHEMISTRY
–period 2, – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 3,4 (LAB) – I. 3(C) 4(A,C) AP CHEMISTRY
-period 3,4 (LAB) – R 3(C) 4(A,C) REMOTE INSTRUCTION
9/17 – Thursday – “D” Day – period 2,3 (Lab) – I 2(B,D) 3(D) AP CHEMISTRY
– period 2,3 (Lab) – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 4 – I 3(B) 4(B,D) AP CHEMISTRY
-period 4 – R 3(B) 4(B,D) REMOTE INSTRUCTION
9/18 – Friday “A” Day – period 2,3 (Lab) – I 2(A,C) 3(A) AP CHEMISTRY
–period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – I 3(C) 4(A,C) AP CHEMISTRY
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
9/14 – Monday “A” Day – period 2,3 (Lab) – I 2(A,C) 3(A) AP CHEMISTRY
-period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – I 3(C) 4(A,C) AP CHEMISTRY
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
– period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION – Please click to the REMOTE instruction week 2 page
– period 2,3 (Lab) – I 2(A,C) 3(A) AP CHEMISTRY – Blue Team is here and has a double period.
-period 4 – I 3(C) 4(A,C) AP CHEMISTRY – single period
MAIN FOCUS: To identify the voltage change in a voltaic cell due to Le Chatelier’s Principle with changes in the concentrations of ions in half cells, specifically when a precipitate is made.
1. Quick Review of the LeChateliers principle worksheet p.pdf – Keep connecting to the U diagram
2. Revisit the Classroom Daniell cell and predict voltage
by diluting the Reduction half cell ( Cu/Cu+2 ) or Blue One with water!!!
By adding water Cu+2 ion solution (molarity) decreased and thus the
Voltage Decreased!!!! Explained in terms of LeChateliers Principle and Spontaneity!
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
Stress: decreases
Response: <—————– Shift = voltage drop!
(lowers spontaneity of forward reaction)
The reverse is now favored more than it was which LOWERS the forwards reactions
pathways or spontaneity, which results in lowering the voltage!
Last Friday I added water to the copper half cell and the voltage increased because I was
decreasing the molarity of the concentration of the Zn+2 ions.
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
Stress: decreases
Response: Shift ———————> = Voltage increase!
(increases spontaneity of forward reaction)
We can decrease the concentration of dissolves ions (aq) another way besides adding water.
3. Precipitation reaction demo – Double replacement reactions or precipitation reactions-
Net ion reaction written to eliminate spectators!
A) Wrote the precipitation reaction between lead (II) nitrate and potassium nitrate.
We used the following worksheet:
B) Particular Diagrams
C) Identified the precipitate.
D) Performed the demonstration.
Today’s demonstration:
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4. Revisit the Classroom Daniell cell and predict voltage by making the Zn+2 ions precipitate out with Na2CO3
being added to the Zn/Zn+2 half cell.
*By adding Na2CO3 I was really delivering CO3–2 ions to the oxidation half cell because Na2CO3 is soluble due to the group one ion (Na+) that has weak Coulombic attractions with the CO3–2 in the salt (ionic compound).
Na2CO3 (s) —-> 2 Na+ (aq) + CO3-2 (aq)
Then CO3-2 reacted with Zn+2 to form a precipitate, which takes Zn+2 out of the solution.
Zn+2 (aq) + CO3-2 (aq) ——> ZnCO3 (s) which is a precipitate = insoluble
Lowering the Zn+2 will cause the overall reaction in the Daniell cell to “shift” Right or be move spontaneous in the forward direction increasing the voltage.
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
Stress: decreases
Response: Shift —————–>
The forward reaction is now more favorable or spontaneous than the reverse thus
the voltage increases (becomes more positive)!
Video of the shifts on the Daniell cell that were described today in the notes above.
*Notice that the voltage does drop after the initial decrease of the voltage from creating the precipitate.
-period 4 – I 3(C) 4(A,C) AP CHEMISTRY – single period – Orange TEAM STOPS Here.
– period 2,3 (Lab) – I 2(A,C) 3(A) AP CHEMISTRY – Blue Team continues on to LAB as it has a double period.
5. Lab 1 – constructing a Voltaic Cell- “Run the radio”
Intro Voltaic Cells worksheet 2 – skills Key p.pdf
Solubility Animation: How salt (ionic compounds) dissolve IF SOLUBLE (weak Coulombic attractions)!
Today’s Period 4 class lecture:
Classwork on worksheet:
9/14 – Monday – Homework: completing the other side of the 2 worksheets that have been
assigned previously.
*ALL CLASSES!
1. Please complete Intro Voltaic Cells Worksheet 1
BUT PLEASE Complete QUESTION 2 ONLY!!
THIS IS THE SIDE THAT HAS the TITLE. (OPPOSITE OF LAST NIGHT’s HW).
Sorry both sides are numbered 1!
2. Review question 2 with the key below.
3. And/or you can follow along with me going over Question 2 with lecture below.
4. Complete ONLY Question 2 (AP Question 2003 side)
Intro Voltaic Cells worksheet 1.pdf worksheet –
( It is a Past AP problem worksheet) –
5. Review with key or the video posted below. (Just question 2!)
9/15 – Tuesday – “B” Day –period 2, – I 2(B,D) 3(D) AP CHEMISTRY –
– period 2, – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 3,4 (LAB) – I 3(B) 4(B,D) AP CHEMISTRY
-period 3,4 (LAB) – R 3(B) 4(B,D) REMOTE INSTRUCTION
– period 2, – R 2(B,D) 3(D) REMOTE INSTRUCTION – please go to the REMOTE page
– period 3,4 (LAB) – R 3(B) 4(B,D) REMOTE INSTRUCTION – Please go to the REMOTE page
–period 2, – I 2(B,D) 3(D) AP CHEMISTRY – single period
-period 3,4 (LAB) – I 3(B) 4(B,D) AP CHEMISTRY – Double Period Lab
Quiz Wednesday and Thursday on everything that we have done! The Intro Voltaic Cells worksheet 1.pdf and The Intro Voltaic Cells worksheet 2.pdf worksheet are KEY! Dig into the lectures that go with them!
Wednesday Quiz: BLUE & ORANGE TEAMS WEDNESDAY
– period 2, – I 2(A,C) 3(A) AP CHEMISTRY
-period 3,4 (LAB) – I. 3(C) 4(A,C) AP CHEMISTRY
Thursday Quiz: RED & GREEN TEAMS THURSDAY
– period 2,3 (Lab) – I 2(B,D) 3(D) AP CHEMISTRY
-period 4 – I 3(B) 4(B,D) AP CHEMISTRY
1. Review of the Daniell cell with 2 stresses in video posted yesterday.
A) Dilution of an ion: Adding water that will lower the molarity = ratio of amount of ions to volume of water
B) Adding a salt that causes a precipitate that lowers the molarity of an ion.– question 1: Intro Voltaic Cells
worksheet 2 – skills
C) Adding a salt that provides a common ion. – question 2: Intro Voltaic Cells
worksheet 2 – skills
* B) and C) only have an effect on changing voltage or spontaneity of the forward direction of the redox reaction if the ion that is effected is in the overall reaction! For the Daniell cell is must be:
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
So only the Cu+2 or Zn+2 are the ions and their concentration changes that can create a stress that will cause the reaction to shift (become more favorable). If the ion is NOT COMMON to the overall reaction of the redox reaction (in the voltaic cell) then there will no effect on spontaneity or voltage.
Positive volts = Favorable Pathway = Spontaneous = entropy of universe (∆S) increasing = energy dispersed = obtain Free Energy (∆G) to do work (power our phones!)
Video of the shifts on the Daniell cell that were described today in the notes above (1A, 1B).
Period 4 Lab – only for Green Team – 3(B) 4(B,D) AP CHEMISTRY – Double Period Lab
1. Lab 1 – Complete the diagram of the voltaic cell on page 2 and all conclusion questions.
Use your picture on your phones to help with the diagram.
– Reviewed the charges ion the anode (-) and cathode (-)
2. Completed Questions 1 – 4 in the conclusion page.
3. Started answering questions 5, 6, 7, 8
question 6: I should NOT have written that the Cu ions cannot pass through the dialysis tubing
question 7: what ions flowing can pass through the Dialysis Tubing (cellulose).
question 8: What is fizzing – I will get to this the next lab period.
-Error Analysis
Conclusion: START YOUR CONCLUSION.
Period 3 recorded Lesson:
9/15 – Tuesday – Homework:
1: Please Study for a 15 minute – 1 page Quiz the voltaic Cell Wednesday 9/15.
A very good review would be to review and redo the following worksheets And/Or Re-vist the videos that went over this weeks topics:
Topics:
A) Labeling a complete voltaic cell:
1. Identify Anode and Cathode.
2. Determine the flow of electrons.
3. Label all ions in half cells (oxidation and reduction areas) AND in Salt Bridge.
4. Movement of ions in salt bridge.
B) Write the Half reactions.
C) Determine the overall Balanced Net ion reaction.
D) Calculate the Net Potential (E0 cell) of the voltaic cell.
E) Predict how the voltaic cell’s voltage will change in response to stress.
Underlying Principles:
Coulombs Law, Le Chatelier’s Principle, Voltage vs Amperage, Spontaneity and Equilibrium,
Solubility and Precipitates, Reduction potentials.
9/16 – Wednesday “C” Day – period 2, – I 2(A,C) 3(A) AP CHEMISTRY
–period 2, – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 3,4 (LAB) – I. 3(C) 4(A,C) AP CHEMISTRY
-period 3,4 (LAB) – R 3(C) 4(A,C) REMOTE INSTRUCTION
TODAY WE ARE IN FULL REMOTE LEARNING:
This means everyone will take the quiz today remotely!
PERIOD 2:
Period 2 Class is now combined with blue team and red team as your scheduled class time is
8:15 – 9:00. We will have the quiz remotely. I will send you a link that you will only have access to during that period.
I will ask everyone to join the Zoom Meeting and keep their computers open to monitor the quiz.
Period 2 – Zoom meeting info:
Topic: AP Chemistry – Period 2 – 9/16 –
Time: Sep 16, 2020 08:00 AM Eastern Time (US and Canada)
Join Zoom Meeting
I will REMIND out the link!
PERIOD 3 – 4: We will use the period 3 for the quiz. Period 4 will be lab.
Period 3 – 4 Class is now combined with the orange team and the green team as your scheduled class time is 9:00 – 9:45. We will have the quiz remotely. I will send you a link that you will only have access to during that period.
I will ask everyone to join the Zoom Meeting and keep their computers open to monitor the quiz.
Period 4 – Zoom meeting info:
I will Remind out the Link!
Period 4 Lab:
1. Started answering questions 5, 6, 7, 8 from Lab
question 6: I should NOT have written that the Cu ions cannot pass through the dialysis tubing….
question 7: What ions flowing can pass through the Dialysis Tubing (cellulose).
question 8: What is fizzing – I will get to this the next lab period.
-Error Analysis
Chemical reactions that may have contributed:
Mg + HOH (water) —–> Mg+2 + 2OH– + H2 (g)
Would these ions (Mg+2 + 2OH–) form a precipitate with ions already present? The color of the entire battery was bluish? What does that say about movement of Cu+2 ions?
What factors were competing? Based on the experimental voltage which factor dominated?
My video below illustrates the reaction occurring above (the fizzing or production of hydrogen gas).
EXTRA HELP 9/16
Time: Sep 16, 2020 02:30 PM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/81610582728?pwd=cElDbnVjNnYzMTFmQW54K0UvTWIvQT09
Meeting ID: 816 1058 2728
Passcode: 94S3JG
One tap mobile
+16465588656,,81610582728#,,,,,,0#,,048924# US (New York)
9/16 – Wednesday “C” Day – Homework:
1. Please view the video posted below to review today’s quiz.
End of Wednesday..
9/17 – Thursday – “D” Day – period 2,3 (Lab) – I 2(B,D) 3(D) AP CHEMISTRY
– period 2,3 (Lab) – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 4 – I 3(B) 4(B,D) AP CHEMISTRY
-period 4 – R 3(B) 4(B,D) REMOTE INSTRUCTION
period 2,3 (Lab) – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 4 – R 3(B) 4(B,D) REMOTE INSTRUCTION
Blue and Orange Team are REMOTE today! Please move to the Remote page!
– period 2,3 (Lab) – I 2(B,D) 3(D) AP CHEMISTRY – 2 periods
-period 4 – I 3(B) 4(B,D) AP CHEMISTRY
ALL voltaic quizzes have been graded and returned by email!
I will show you how I graded it and take questions.
You can take a make-up tomorrow to get the better out of 2 grades.
1: Today’s demonstration: Concentration Cell
2. Started answering questions 5, 6, 7, 8 from Lab
question 6: I should NOT have written that the Cu ions cannot pass through the dialysis tubing….
question 7: What ions flowing can pass through the Dialysis Tubing (cellulose).
question 8: What is fizzing – I will get to this the next lab period.
-Error Analysis
Chemical reactions that may have contributed:
Mg + HOH (water) —–> Mg+2 + 2OH– + H2 (g)
Would these ions (Mg+2 + 2OH–) form a precipitate with ions already present? The color of the entire battery was bluish? What does that say about movement of Cu+2 ions?
What factors were competing? Based on the experimental voltage which factor dominated?
My video below illustrates the reaction occurring above (the fizzing or production of hydrogen gas).
START YOUR CONCLUSION.
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Conclusion Writing: 1. What did find or measure Quantitatively? What are the important values of your data? This is normally posted in your results section of a formal writeup. How accurate are you (how close are you to a known standard, E0 cell )?
2. Make the leap! = connect your quantitative value and comparison with the known standard in terms of atom/ions or particle to explain a possibly reason for the outcome.
3. Error discussion.
Every laboratory is limited in errors in measurement and human errors. Do not write about these!! Please describe in detail every major limitation of this laboratory and why you believe it may have lead to your outcome.
IN this Lab the error discussion will result from things that are NOT FROM YOUR LEAP! Do nor just list errors. I want an explaination how these errors could of resulted in YOUR OUTCOME.
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Lab 1 Conclusion review:
1. Please tell me what you measured (voltage) and calculated (percent error). Do not mince words. Get to the point. This is like our results section last year in our formal labs.
2/3: Explain your errors (why your percent error was so low or negative). You will combine the leap with the error analysis here. The leap last year was always about an organism and the leap this year is always about atoms or ions. So what did the atoms or ions do that may have contributed to the large negative error? There is one error that is the largest and I like to think of it as a love triangle between Mg, Cu+2 , and H2O. I think this was the inspiration to Ed Sheeran’s song, Happier.
I saw you in another’s arms
Only a month we’ve been apart You look happier Saw you walk inside a bar
He said something to make you laugh I saw that both your smiles were twice as wide as ours Yeah, you look happier, you do Ain’t nobody hurt you like I hurt you
But ain’t nobody love you like I do Promise that I will not take it personal, baby If you’re moving on with someone new ‘Cause baby you look happier, you do
My friends told me one day I’ll feel it too And until then I’ll smile to hide the truth But I know I was happier with you Sat on the corner of the room
Everything’s reminding me of you Nursing an empty bottle and telling myself you’re happier Aren’t you? Ain’t nobody hurt you like I hurt you
But ain’t… |
 This cell was left over night. Notice the Mg electrode is smaller and the cloudy mixture. Were there precipitates?
How did this contribute to the error? Or was this a competing error? Notice some of the precipitates seem to be bluish green, which is an indication that Copper precipitates were also made.
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Today’s Class lecture:
9/17 – Thursday – “D” Day homework –
Today’s 2(B,D) 3(D) REMOTE Instruction – students will take the make-up in class tomorrow
Today’s 4(B,D) REMOTE Instruction – students will take the make-up in class tomorrow
Today’s 2(B,D) 3(D) AP CHEMISTRY students will take the Make-up in class Monday.
Today’s 3(B) 4(B,D) AP CHEMISTRY students will take the Make-up in class Monday
1. Review your quiz with the key posted in powerschool or with the video below:
Voltaic Quiz review:
2. Complete questions 6 (skip last question in 6) and 3 from the worksheets below. I will post a key later today.
Recent Voltaic Cell AP Test Questions .pdf
End of Thursday..
9/18 – Friday “A” Day – period 2,3 (Lab) – I 2(A,C) 3(A) AP CHEMISTRY
–period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – I 3(C) 4(A,C) AP CHEMISTRY
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
–period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
RED TEAM and Green Team are Remote today. Please go to the Remote page.
period 2,3 (Lab) – I (2 periods)
-period 4 – I – (single period )
Period 2: – Will be Zoom streamed
1. We will review the Recent Voltaic Cell AP Test Questions .pdf worksheet (questions 6 and 3).
2. We will take Make-up Voltaic Cell Quiz. I love giving quizzes and tests back quickly but I have to wait till the other classes take it before I release the graded quiz back to you.
Period 3: Lab
1. Build the voltaic cell one last time and complete the conclusion questions.
2. Start the conclusion.
We will use the information posted above for the lab questions and the conclusion writing.
Period 4: (same as period 2)-
Lab 1 – REVIEW – Period 3 –
9/18 – Friday “A” Day Homework –
1. Complete the form below on battery in your car (lead acid) UNLESS
its an electric car (Lithium Ion). You have a total of 3 submissions to this form.
2. Complete Lab 1 by writing the conclusion. You can write by hand (neatly) or you can type and add it to the back of the lab. Please watch the period 3 video or stream to complete the questions and how to write the conclusion. I will post these resources below the lead acid battery materials below.
REMOTE STUDENTS – PLEASE use the Voltaic Cell Lab Video below to start and complete the lab.
Use the links below the description to help complete the lab. If cannot print then write out the lab on a separate piece of paper.
Please use the lab conclusion rubric posted above in THURSDAY
and the VIDEO POSTED ABOVE (Lab 1 – REVIEW – Period 3 -)
Lab 1 is due Monday – (handed in) – for the RED and GREEN team who are REMOTE today.
Lab 1 is due Tuesday– (handed in) – for the BLUE and ORANGE team who are In Person today.
Battery Form:
Lead acid Battery (Car Battery):
How It Works
Let me give you the big picture first for those who aren’t very detail oriented. Basically, when a battery is being discharged, the sulfuric acid in the electrolyte is being depleted so that the electrolyte more closely resembles water. At the same time, sulfate from the acid is coating the plates and reducing the surface area over which the chemical reaction can take place. Charging reverses the process, driving the sulfate back into the acid. That’s it in a nutshell, but read on for a better understanding. If you’ve already run from the room screaming and pulling your hair, don’t worry.
The electrolyte (sulfuric acid and water) contains charged ions of sulfate and hydrogen. The sulfate ions are negatively charged, and the hydrogen ions have a positive charge. Here’s what happens when you turn on a load (headlight, starter, etc). The sulfate ions move to the negative plates and give up their negative charge. The remaining sulfate combines with the active material on the plates to form lead sulfate. This reduces the strength of the electrolyte, and the sulfate on the plates acts as an electrical insulator. The excess electrons flow out the negative side of the battery, through the electrical device, and back to the positive side of the battery. At the positive battery terminal, the electrons rush back in and are accepted by the positive plates. The oxygen in the active material (lead dioxide) reacts with the hydrogen ions to form water, and the lead reacts with the sulfuric acid to form lead sulfate.
The ions moving around in the electrolyte are what create the current flow, but as the cell becomes discharged, the number of ions in the electrolyte decreases and the area of active material available to accept them also decreases because it’s becoming coated with sulfate. Remember, the chemical reaction takes place in the pores on the active material that’s bonded to the plates.
Lead Acid battery 1 video:
Lead Acid battery animation:
PbO2(s) + HSO–4 (aq) + 3H+ (aq) + 2e– —> PbSO4 (s) + 2H2O (l) E0 = + 1.69 V
PbSO4(s) + H+ (aq) + 2e– —-> HSO4– (aq) + Pb (s) E0 = – .35 V
Pb+2 + 2e– —-> Pb0 E0 = – .13 V
End of week 2!
Remote Instruction:
Please Refresh this page every time you visit as I make changes daily and many times during the day.
9/14 – Monday “A” Day – period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
RED TEAM and GREEN Team are REMOTE today!
We will do a LIVE ZOOM Stream TODAY for today’s lesson. The notes for today’s lesson are provided below:
Topic: 9/14 Zoom Stream AP CHEMISTRY
Time: Sep 14, 2020 08:15 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/86352902236?pwd=dXBJY3JBbmovL3NLRnNWekdCVlh4Zz09
Meeting ID: 863 5290 2236
Passcode: 4y6Gcw
One tap mobile
+16465588656,,86352902236#,,,,,,0#,,510353# US (New York)
Link to today’s Recorded Zoom Stream:
https://drive.google.com/file/d/1PktkpBFWRAo_hDAduxlNCjjBBWt4Yypt/view?usp=sharing
MAIN FOCUS: To identify the voltage change in a voltaic cell due to Le Chatelier’s Principle with changes in the concentrations of ions in half cells, specifically when a precipitate is made.
1. Quick Review of the LeChateliers principle worksheet p.pdf – Keep connecting to the U diagram
2. Revisit the Classroom Daniell cell and predict voltage
by diluting the Reduction half cell ( Cu/Cu+2 ) or Blue One with water!!!
By adding water Cu+2 ion solution (molarity) decreased and thus the
Voltage Decreased!!!! Explained in terms of LeChateliers Principle and Spontaneity!
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
Stress: decreases
Response: <—————– Shift = voltage drop!
(lowers spontaneity of forward reaction)
The reverse is now favored more than it was which LOWERS the forwards reactions
pathways or spontaneity, which results in lowering the voltage!
Last Friday I added water to the copper half cell and the voltage increased because I was
decreasing the molarity of the concentration of the Zn+2 ions.
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
Stress: decreases
Response: Shift ———————> = Voltage increase!
(increases spontaneity of forward reaction)
We can decrease the concentration of dissolves ions (aq) another way besides adding water.
3. Precipitation reaction demo – Double replacement reactions or precipitation reactions-
Net ion reaction written to eliminate spectators!
A) Wrote the precipitation reaction between lead (II) nitrate and potassium nitrate.
We used the following worksheet:
B) Particular Diagrams
C) Identified the precipitate.
D) Performed the demonstration.
Today’s demonstration:
|
|
|
4. Revisit the Classroom Daniell cell and predict voltage by making the Zn+2 ions precipitate out with Na2CO3
being added to the Zn/Zn+2 half cell.
*By adding Na2CO3 I was really delivering CO3–2 ions to the oxidation half cell because Na2CO3 is soluble due to the group one ion (Na+) that has weak Coulombic attractions with the CO3–2 in the salt (ionic compound).
Na2CO3 (s) —-> 2 Na+ (aq) + CO3-2 (aq)
Then CO3-2 reacted with Zn+2 to form a precipitate, which takes Zn+2 out of the solution.
Zn+2 (aq) + CO3-2 (aq) ——> ZnCO3 (s) which is a precipitate = insoluble
Lowering the Zn+2 will cause the overall reaction in the Daniell cell to “shift” Right or be move spontaneous in the forward direction increasing the voltage.
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
Stress: decreases
Response: Shift —————–>
The forward reaction is now more favorable or spontaneous than the reverse thus
the voltage increases (becomes more positive)!
Video of the shifts on the Daniell cell that were described today in the notes above.
*Notice that the voltage does drop after the initial decrease of the voltage from creating the precipitate.
HOMEWORK AS ALWAYS IS POSTED IN in the NON REMOTE class webpage.
9/15 – Tuesday – “B” Day – period 2, – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 3,4 (LAB) – R 3(B) 4(B,D) REMOTE INSTRUCTION
The BLUE and Orange Team are remote today!
We will do a LIVE ZOOM Stream TODAY for today’s lesson. The notes for today’s lesson are provided below:
Topic: 9/15 AP Chemistry review lesson
Time: Sep 15, 2020 08:15 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/86436551241?pwd=MkNXMi9Wd3N6R2JWenVncWZGOGFCdz09
Meeting ID: 864 3655 1241
Passcode: 1jjUFE
One tap mobile
+16465588656,,86436551241#,,,,,,0#,,428559# US (New York)
LINK to the today’s RECORDED Live stream:
https://drive.google.com/file/d/1ufe5z1wFpoZ-q_3MEW_6TZX3fWnyKc5F/view?usp=sharing
Quiz Wednesday and Thursday on everything that we have done! The Intro Voltaic Cells worksheet 1.pdf and The Intro Voltaic Cells worksheet 2.pdf worksheet are KEY! Dig into the lectures that go with them!
Wednesday Quiz: BLUE & ORANGE TEAMS WEDNESDAY
– period 2, – I 2(A,C) 3(A) AP CHEMISTRY
-period 3,4 (LAB) – I. 3(C) 4(A,C) AP CHEMISTRY
Thursday Quiz: RED & GREEN TEAMS THURSDAY
– period 2,3 (Lab) – I 2(B,D) 3(D) AP CHEMISTRY
-period 4 – I 3(B) 4(B,D) AP CHEMISTRY
1. Review of the Daniell cell with 2 stresses in video posted yesterday.
A) Dilution of an ion: Adding water that will lower the molarity = ratio of amount of ions to volume of water
B) Adding a salt that causes a precipitate that lowers the molarity of an ion.– question 1: Intro Voltaic Cells
worksheet 2 – skills
C) Adding a salt that provides a common ion. – question 2: Intro Voltaic Cells
worksheet 2 – skills
* B) and C) only have an effect on changing voltage or spontaneity of the forward direction of the redox reaction if the ion that is effected is in the overall reaction! For the Daniell cell is must be:
Zn0 (s) + Cu+2 —–> Zn+2 + Cu0
So only the Cu+2 or Zn+2 are the ions and their concentration changes that can create a stress that will cause the reaction to shift (become more favorable). If the ion is NOT COMMON to the overall reaction of the redox reaction (in the voltaic cell) then there will no effect on spontaneity or voltage.
Positive volts = Favorable Pathway = Spontaneous = entropy of universe (∆S) increasing = energy dispersed = obtain Free Energy (∆G) to do work (power our phones!)
Video of the shifts on the Daniell cell that were described today in the notes above (1A, 1B).
Period 4 Lab – only for Green Team
Please check week 2 for class homework.
9/16 – Wednesday – “C” Day –
Please visit week 2 page as we are in FULL REMOTE INSTRUCTION TODAY.
9/17 – Thursday – “D” Day –
period 2,3 (Lab) – R 2(B,D) 3(D) REMOTE INSTRUCTION
-period 4 – R 3(B) 4(B,D) REMOTE INSTRUCTION
Blue and Orange Team are REMOTE today!
– period 2,3 (Lab) – I 2(B,D) 3(D) AP CHEMISTRY – 2 periods
-period 4 – I 3(B) 4(B,D) AP CHEMISTRY
ALL voltaic quizzes have been graded and returned by email!
I will show you how I graded it and take questions.
You can take a make-up tomorrow to get the better out of 2 grades.
2(B,D) 3(D) REMOTE INSTRUCTION – students will take the make-up in class tomorrow
4(B,D) REMOTE INSTRUCTION – students will take the make-up in class tomorrow
ZOOM meeting info:
Mr. Grodski is inviting you to a scheduled Zoom meeting.
Topic: AP Chemistry – 9/17
Time: Sep 17, 2020 08:15 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/86088376000?pwd=bmkzS3ZjeGtXd01veUZReTJKU1FXdz09
Meeting ID: 860 8837 6000
Passcode: ZNX5L3
One tap mobile
+16465588656,,86088376000#,,,,,,0#,,105593# US (New York)
Link to the recorded Zoom Meeting for todays class:
1. Review quiz-
2. Another example of a voltaic cell: Concentration cell – see video below which I used for class. This example should help with the concepts of the quiz.
3. Lab 1 conclusion questions –
SEE week 2 page for homework.
9/18 – Friday “A” Day
–period 2,3 (Lab) – R 2(A,C) 3(A) REMOTE INSTRUCTION
-period 4 – R 3(C) 4(A,C) REMOTE INSTRUCTION
RED and GREEN TEAM are REMOTE today.
These 2 groups will take the Makeup in class MONDAY, along with all the FULL REMOTE STUDENTS.
THE FULL REMOTE STUDENTS will take the quiz in the same fashion as this WEDNESDAY. I will send out a link and notify you of the time over the weekend.
THERE has been a change is which students are FULL REMOTE due to the recent quarantine.
PLEASE EMAIL if your are on quarantine and ARE NOW A FULL REMOTE STUDENT. I do not have the latest changes.
We will live Zoom Steam in the beginning of period 2 to review the homework. You can leave us a bit as we will have a retake quiz for the blue team. YOU WILL BE REJOINING US IN period 3 FOR LAB with new zoom stream ( a new link is provided below) to complete LAB 1!
Topic: AP Chemistry 9/18 period 2
Time: Sep 18, 2020 08:00 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/84887370773?pwd=OTFkQjJZdi9WVzJ5WlhxSzZRME9TUT09
Meeting ID: 848 8737 0773
Passcode: WeULn2
One tap mobile
+16465588656,,84887370773#,,,,,,0#,,696070# US (New York)
Period 2: – Will be Zoom streamed in the beginning
1. We will review the Recent Voltaic Cell AP Test Questions .pdf worksheet (questions 6 and 3).
2. We will take Make-up Voltaic Cell Quiz. I love giving quizzes and tests back quickly but I have to wait till the other classes take it before I release the graded quiz back to you.
We will live Zoom Steam period 3 – To complete the lab and start the conclusion.
Time: Sep 18, 2020 09:00 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/81024377745?pwd=dWpPTjhjNnJMZEtYTTNxMHVjZXE0dz09
Meeting ID: 810 2437 7745
Passcode: 7tAwwX
One tap mobile
+16465588656,,81024377745#,,,,,,0#,,564700# US (New York)
Period 3: Lab: Will be Zoom streamed for Lab and Youtubed (posted later)
1. Build the voltaic cell one last time and complete the conclusion questions.
2. Start the conclusion.
We will use the information posted above for the lab questions and the conclusion writing.
Period 4: (same as period 2)- Will be recorded for youtube.
FULL REMOTE STUDENTS will complete lab 1 with me with a Virtual Lab Video that I will be making this afternoon:
Virtual Lab 1: To be posted this afternoon.
PLEASE READ THE HOMEWORK CAREFULLY in the week 2 page.
End of REMOTE week 2!