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Archive – Q2 week 6 – 20 – 21

Week of 12/21 – 12/23 – Please Refresh every time you open– this page is changing often!

 

The 4 day – A, B, C, D cycle looks like this:
                                                       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
 
        Monday                 In class:          D               Lab                   Lab             Single Class
                                   Remote:                           Lab                   Lab              Single Class
                 
 
This weeks 3 day Schedule:
 
12/21  – Monday “A” Day     – period 2,3 (Lab) –     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
12/22  – 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
 
12/23  –  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
 

12/21  – Monday “A” Day –   period 2,3 (Lab) –     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
 
 
The RED and GREEN team are Remote today. Please move to the Remote Instruction Page.
 
Period 2 : Class lecture – Spectrophotometry Review
 
Connections:
In Lab 13 – Volumetric REDOX Titrations – We used Fe+2 ions to Standardize the KMnOsolution.
The MnO4  solution  oxidized the Fe+2  into Fe+3 .  The Fe+2  reduced the The MnO4  solution to turn from purple (Mn+7 form) to colorless (Mn+2).  
 
IF the the Fe+2  solution sits in volumetric flask it slowly changes into Fe+3 as oxygen in the flask and in the solution oxidizes the the Fe+2 solution. Notice the development of color in the 24 hour period.  
 
 I have to make the  Fe+2  solution fresh each day.  Why is there a color developing?

As the Fe+2  becomes  Fe+3  the solution has a greater ability to absorb wavelengths of visible light because Fe+3 makes a complex ion with water that attracts water with such high Coulombic attractions that the water’s lone pair of electrons are pushed into the iron’s (Fe) d – orbitals directly interfering with some d – orbitals and not others based on their orientation in space.  The orbitals that “feel” the oxygens electrons become destabilized (increase in energy) and there is a spit in the energy level between these orbitals that were initially the same energy.
 
This splitting of d orbital energy levels provides a pathway for electrons to transition to higher energy levels when low energy visible light energy (photons) are absorbed.  Not all of the wavelengths of light are absorbed thus the ones that are not absorbed are what we see.
The spectrophotometer picks up the transmittance (which is the what is absorbed or missing from our eye.)

A photon of light of a certain wavelength is absorbed by electrons in lower energy d orbitals that can now transition into higher energy d orbitals (that split due to electrons being pulled directly into the orbitals). The absorbed photon is now missing from the entire spectrum of light that is illuminating the complex and the color shown is what is left.
 
Period 3, Period 4: Lab 16 – Percent by mass of Cu in a sample of Brass
 
 Lab 16 = percent by mass of NICE copper in Brass – 
                                        a percent by mass lab – need initial mass at the beginning!
 
        a) Set up your spectrophotometer so that it is calibrated (to water in a cuvette), set to measure  
             a peak wavelength (with the .40M solution), 
 
 
        b) Make our serial dilutions to calibrate the spectrophotometer
 
                     0.40 M (Standard),   0.02 M,  0.10M,  0.05M  of Cu(NO3)2
 
        c) Place your four cuvettes of KNOWN concentrations into the spectrophotometer from  
              lowest concentration to highest and type in your concentrations (with Keep button like you  
              did with the Acid /Base titrations.  This is called a Beer’s Law graph. Hit the regression  
              button to make a line of best fit that will also provide the slope and y – intercept data.
              Print this Graph.
 
         d) Dilute the dissolved brass solution (from nitric acid that was added to your brass samples yesterday). You  
             will dilute to 100.0 using a 100.0 ml volumetric flask. Googles and gloves here!
 
         e)  Once diluted to a the known volume, 100.0 ml, all you need to know to determine the percent of copper in  
               the brass sample was obtain it concentration.  You will now fill a an empty cuvette with this solution.            
               Place it into the spectrophotometer and determine its Absorbance.
 
          f) Determine solutions concentration (molarity) using the Beer’s Law graph that was made yesterday (by  
           using linear algebra).
 
          g) Calculate the moles of copper, grams of copper and finally the percent by mass of copper.
Today’s Period Lecture: reviews components of yesterdays form that most people had trouble with 
 
12/21  – Monday “A” Day – Homework – 
 
I am giving no homework over the break BUT we will work until then!
 
1.  Please view the class lecture from period 2 today – It will be posted later today.
     The Blue team and the RED team (remote)  watched this live .
     The Green and ORANGE Team needs to view this lecture!
 
2.  Resubmit a second submission to this weekends form after the class or video review above.
 
3:  Please complete the class worksheet with the lecture and or key. 
    
      Blue team and the Orange Team will complete this tomorrow! 
      The Green and ORANGE Team will complete this tonight!
 
2006 B spectrophotometry question.pdf
View Download
 
2006 B spectrophotometry question key p.pdf
 
4.  Begin or Finish your individual  Slide – up of the Lab 16 – % by mass of Cu in Brass.
       This Lab is due Wednesday!  It really is not a lot and you can take photos of your work.
 
        The Blue team and the Orange Team completed the data gathering today and can begin the   
        write – up. The Red and Green cannot begin this until tomorrow.
 
      Lecture on how to complete the percent copper in brass Lab:
Lab 16 – Non-formal – Write-up requirements:

Informal Lab write – up requirements for Lab 14:

 
1. Title Slide –  Title of Lab / name / date
 
2.  Background SLIDE– How spectrophotometry works/Notes
3. Objective SLIDE:
 
4. DATA SLIDES:
 
    a) Balance reaction between brass (copper only) and nitric acid (HNO3 ) on Data page
 
                                                                     NO3-1   —–>  NO2
                                                                         Cu   ——-> Cu+2
    b) Data table:
 
                a) mass of Brass Shot total
                b) balance nitric acid/calculation
                c) Serial dilution calculations
 
                
    c) Beer’s Law Graph on its own SLIDE  I will post digital copies of each lab
 
    d) final calculation of % by mass of copper in shot – Show all calculations
 
    e) Calculate the absorptivity constant (a) using the absorbance (A) and concentrations (c).
 
                    A = a b c
 
                         Using the absorbance values from the spectrophotometer (A), the path length ( b = 1 cm ), and the 
                         concentrations of these solutions (c) solve for a with the correct units.  Make a chart. These  
                        values that you calculate should be similar as it is a constant.
 
 5Error analysis SLIDE:   The limitation of the lab was based on how well you made the solutions and if the absortivity constant STAYED CONTANT!  I will explain once you finish step e.
 
 
6. Sources SlideIf needed
 
I will explain e) on Wednesday!
 
 
Lecture on how to complete the percent copper in brass Lab:
 
End of Monday!

12/22  – 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
 
The Blue and the Orange Team are remote today. Please move to the Remote Page.
 
Period 2 –  The RED Team will complete Lab 16 in class
 
I will have serial dilutions completed in order to save time.
 
        
Lab 16 = percent by mass of NICE copper in Brass – 
                                        a percent by mass lab – need initial mass at the beginning!
 
        a) Set up your spectrophotometer so that it is calibrated (to water in a cuvette), set to measure  
             a peak wavelength (with the .40M solution), 
 
 
        b) Make our serial dilutions to calibrate the spectrophotometer
 
                     0.40 M (Standard),   0.02 M,  0.10M,  0.05M  of Cu(NO3)2
 
        c) Place your four cuvettes of KNOWN concentrations into the spectrophotometer from  
              lowest concentration to highest and type in your concentrations (with Keep button like you  
              did with the Acid /Base titrations.  This is called a Beer’s Law graph. Hit the regression  
              button to make a line of best fit that will also provide the slope and y – intercept data.
              Print this Graph.
 
         d) Dilute the dissolved brass solution (from nitric acid that was added to your brass samples yesterday). You  
             will dilute to 100.0 using a 100.0 ml volumetric flask. Googles and gloves here!
 
         e)  Once diluted to a the known volume, 100.0 ml, all you need to know to determine the percent of copper in  
               the brass sample was obtain it concentration.  You will now fill a an empty cuvette with this solution.            
               Place it into the spectrophotometer and determine its Absorbance.
 
          f) Determine solutions concentration (molarity) using the Beer’s Law graph that was made yesterday (by  
           using linear algebra).
 
Period 3,4 – Lab 16 complete Lab with calculations completed
 
12/22  – Tuesday   “B” Day Homework:
 
 
1:  Please complete the class worksheet with the lecture and or key. 
    
      Blue team and the Orange Team will complete this tonight! 
      
The Green and ORANGE Team should have completed this last night!
 
2006 B spectrophotometry question.pdf
View Download
 
2006 B spectrophotometry question key p.pdf
 
 
2.  LAB 16 Slide – up (informal lab write-up on a Google presentation) is due Tomorrow!!
 
Begin or Finish your individual  Slide – up of the Lab 16 – % by mass of Cu in Brass.
       This Lab is due Wednesday!  It really is not a lot and you can take photos of your work.
 
I have posted what is required on the presentation for Lab 16 above (under Monday’s homework).
 
        The Blue team and the Orange Team completed the data gathering yesterday and can complete the  write – up in the shared google slides that I shared yesterday. The Red and Green can now complete this tonight as we have completed the lab today.
 
3. Please review the concepts that are related the last 2 labs:
 
                a)  Lab 15 – Volumetric Titration of Oxalic Acid – (redox titration)
 
                 b) Lab 16 – Percent Cu in a Brass ( spectrophotometry)
 
We will have a single period Test tomorrow on the concepts of these labs.
 
End of Tuesday..

12/23  –  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
The RED Team and the Green Team are Remote.  Please move to the Remote Instruction Page.
 
Period 2:
 
Lab 15 and Lab 16 test – one period
Period 3:
Lab 15 and Lab 16 test – one period
 
Period 4:
 
Holiday Frolicking!
 
12/23  –  Wednesday –  “C” Day Homework:      
1. Please check the counter daily and fill the form below to prove your diligence.
 

 

 

End of week 6 and the End of 2020!

 REMOTE INSTRUCTION:
2/21  – Monday “A” Day –   period 2,3 (Lab) –     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
The RED and GREEN team are Remote today.
ZOOM Stream info:
Topic: AP Chemistry – 12.21 – Period 2, 3 and 4
Time: Dec 21, 2020 08:00 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/84858178151?pwd=SEhwWGp3Rk5LVndvaTN0aUN0V2Rndz09
Meeting ID: 848 5817 8151
Passcode: Tu3cZs
One tap mobile
+16465588656,,84858178151#,,,,*842239# US (New York)
 
Period 2 : Class lecture – Spectrophotometry Review
 
Connections:
In Lab 13 – Volumetric REDOX Titrations – We used Fe+2 ions to Standardize the KMnOsolution.
The MnO4  solution  oxidized the Fe+2  into Fe+3 .  The Fe+2  reduced the The MnO4  solution to turn from purple (Mn+7 form) to colorless (Mn+2).  
 
IF the the Fe+2  solution sits in volumetric flask it slowly changes into Fe+3 as oxygen in the flask and in the solution oxidizes the the Fe+2 solution. Notice the development of color in the 24 hour period.  
 
 I have to make the  Fe+2  solution fresh each day.  Why is there a color developing?

As the Fe+2  becomes  Fe+3  the solution has a greater ability to absorb wavelengths of visible light because Fe+3 makes a complex ion with water that attracts water with such high Coulombic attractions that the water’s lone pair of electrons are pushed into the iron’s (Fe) d – orbitals directly interfering with some d – orbitals and not others based on their orientation in space.  The orbitals that “feel” the oxygens electrons become destabilized (increase in energy) and there is a spit in the energy level between these orbitals that were initially the same energy.
 
This splitting of d orbital energy levels provides a pathway for electrons to transition to higher energy levels when low energy visible light energy (photons) are absorbed.  Not all of the wavelengths of light are absorbed thus the ones that are not absorbed are what we see.
The spectrophotometer picks up the transmittance (which is the what is absorbed or missing from our eye.)
A photon of light of a certain wavelength is absorbed by electrons in lower energy d orbitals that can now transition into higher energy d orbitals (that split due to electrons being pulled directly into the orbitals). The absorbed photon is now missing from the entire spectrum of light that is illuminating the complex and the color shown is what is left.
 
Period 3Period 4: Lab 16 – Percent by mass of Cu in a sample of Brass
OK I will be working with the in-class teams on Lab 16.  You guys should work on the homework
worksheet and lecture AND THEN make another submission to this weekends form.
 
You guys will complete the lab tomorrow in class.
 
FULL REMOTE STUDENTS I will have a LIVE Lab Stream for Lab 16 tomorrow so that you can gather the data and complete the lab.
 
Please move to the week 6 page so that you can view the homework.
No homework over the break but we will work until then!
 

12/22  – 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
 
The Blue and the Orange Team are remote today. 
 
 
ZOOM Stream info:
Topic: AP Chemistry – 12.22 – Periods 2,3,4
Time: Dec 22, 2020 08:00 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/87089228085?pwd=THJLWnlwWUFqV2ZMZFdCUlZ5T21Mdz09
Meeting ID: 870 8922 8085
Passcode: Dj4kkB
One tap mobile
+16465588656,,87089228085#,,,,*372734# US (New York)
 
 
Period 2 –  The RED Team will complete Lab 16 in class
 
The Blue Team can work on the Write up on the google presentation that was linked to you yesterday. You can also work on homework worksheet (#1 of the homework).
 
FULL REMOTE STUDENTS I WILL STREAM THE LAB this period 3 and post this video.
        
Lab 16 = percent by mass of NICE copper in Brass – 
                                        a percent by mass lab – need initial mass at the beginning!
 
        a) Set up your spectrophotometer so that it is calibrated (to water in a cuvette), set to measure  
             a peak wavelength (with the .40M solution), 
 
 
        b) Make our serial dilutions to calibrate the spectrophotometer
 
                     0.40 M (Standard),   0.02 M,  0.10M,  0.05M  of Cu(NO3)2
 
        c) Place your four cuvettes of KNOWN concentrations into the spectrophotometer from  
              lowest concentration to highest and type in your concentrations (with Keep button like you  
              did with the Acid /Base titrations.  This is called a Beer’s Law graph. Hit the regression  
              button to make a line of best fit that will also provide the slope and y – intercept data.
              Print this Graph.
 
         d) Dilute the dissolved brass solution (from nitric acid that was added to your brass samples yesterday). You  
             will dilute to 100.0 using a 100.0 ml volumetric flask. Googles and gloves here!
 
         e)  Once diluted to a the known volume, 100.0 ml, all you need to know to determine the percent of copper in  
               the brass sample was obtain it concentration.  You will now fill a an empty cuvette with this solution.            
               Place it into the spectrophotometer and determine its Absorbance.
 
          f) Determine solutions concentration (molarity) using the Beer’s Law graph that was made yesterday (by  
           using linear algebra).
 
Period 3,4 – The Green team will complete Lab 16 in class
 
The orange team can work on the write-up in the google slides that was shared yesterday.
You can also work on homework worksheet (#1 of the homework).
 
FULL REMOTE STUDENTS I WILL STREAM THE LAB this period.
 
Lab 16 Data – Beer’s Law Graph with linear regression:
Full Remote Spectrophotometry lab data.pdf
View Download
 
I will post the Video of the Lab 16 Stream:

12/23  –  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
The RED Team and the Green Team are Remote today.  
 
ZOOM Stream info:
Topic: AP Chemistry – 12.23 – Periods 2,3, 4
Time: Dec 23, 2020 08:00 AM Eastern Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/89908076790?pwd=cTEwS3FmRnhLc2ZMK0RRWVphUGF0Zz09
Meeting ID: 899 0807 6790
Passcode: t8FwFh
One tap mobile
+16465588656,,89908076790#,,,,*095293# US (New York)
 
 
Period 2:
 
Lab 15 and Lab 16 test – one period
Period 3:
Lab 15 and Lab 16 test – one period
 
Period 4:
 
Holiday Frolicking!
 
Please move to the week 6 page to view the holiday break homework 🙁