Archive – Q2 week 3 – 19-20
Week of 11/18 – 11/22
11/18 – Monday – period 2/3
1. TUMs Lab –
a) Standardize the Base!
b) Perform the lab based on YOUR procedure!
1) Crush Tabs (2)
2) Add excess acid
3) Titrate Excess
4) Calculate the milligrams per tablet.
– period 4
1. TUMs Lab –
a) Standardize the Base!
b) Perform the lab based on YOUR procedure!
1) Crush Tabs (2)
2) Add excess acid
3) Titrate Excess
11/18 – Monday – Homework:
1. Formal Lab Write-up of the Lab 11 – Determination of active ingredient in TUMS (750 EXTRA!)
a) Data Table Complete!
b) Calculations page complete – typed calculations!
c) Results page complete.
D) Conclusion page – NOT due yet.
Video to help with calculations:
End of Monday!
11/19 – Tuesday – period 2 –
1. Classwork – Work together in Lab groups to complete the following Form that will help understand your TUMs lab and help with the aspirin lab that we will begin tomorrow..
Please use the hardcopies of the form to help complete. This form is based on a design of a lab for another over the counter medication that will be very similar to the aspirin (BUT NOT THE SAME) that we will begin tomorrow. Remember that you will be using a back titration as the active ingredient in Advil (Naproxen) is a weak (acid or base). Use your procedure in the TUMS lab to help solve this form which will compromise the calculations and steps needed to complete the quality control lab of the active ingredient of AleveTM .
The form will be on auto- reply and you have 3 replies individually. I will send out the handwritten when everyone has completed their responses from both classes.
– period 3/4-
1. Classwork – Work together in Lab groups to complete the following Form that will help understand your TUMs lab and help with the aspirin lab that we will begin tomorrow..
Please use the hardcopies of the form to help complete. This form is based on a design of a lab for another over the counter medication that will be very similar to the aspirin (BUT NOT THE SAME) that we will begin tomorrow. Remember that you will be using a back titration as the active ingredient in Advil (Naproxen) is a weak (acid or base). Use your procedure in the TUMS lab to help solve this form which will compromise the calculations and steps needed to complete the quality control lab of the active ingredient of AleveTM .
The form will be on auto- reply and you have 3 replies individually. I will send out the handwritten when everyone has completed their responses from both classes.
Quality Control of Aleve Form:
11/19 – Tuesday Homework: TUMS LAB DUE Tomorrow –
1. Complete the Aleve Form- 3 submissions per person.
Careful about your sig figs!
2. Complete the TUMS lab with a conclusion. Conclusions DO NOT INCLUDE ANOTHER PROCEDURE!!
Your conclusion will include the the explanation of the data written in your results sections. It will include error analysis. This is a very accurate lab but there are places in the procedure that error COULD of occurred. Please try to evaluate those possible instances AND HOW THEY explain YOUR results. How have the amount of errors in this experiment been controlled or limited? What was done to maximize accuracy? Do not just state this was an accurate lab. You need to explain why!
Everyone determined that the amount of active ingredient was UNDER the reported value (750 mg per tablet). What are the implications of this quality control experiment considering that our errors have been controlled or limited in our design of the experiment. What does your outcome as the quality control chemist mean for the consumer or the company.
End of Tuesday..
11/20 – Wednesday – period 2/3
You will determine the milligrams of aspirin by using 2 tablets of Bayer. Please look at the molecular structures of aspirin below to begin your lab design. Acetylsalicylic acid (aspirin) gets hydrolyzed into 2 components in water.
This is a slow reaction that can be increased by temperature and excess chemical (Le Chateliers principle).
Identification of organic acids can done by Table R in our Regents Chemistry reference tables:
1. Lab 12 – Determination of Aspirin in Bayer
Lab Assistant Ben!
period 4
1. Lab 12 – Determination of Aspirin in Bayer
Lab Assistant Ben!
Lab 12 – Aspirin Lab Test Requirements:
a: Using the Google Doc that is shared individually, start determining the procedure necessary to determine the amount of aspirin in a Bayer tablet.
USE THE TUMS LAB AS A GUIDE!!!
b: Understanding Lab 11 will help here. You need to figure out what chemicals you need and what their Molarities will need to be to successfully titrate aspirin.
You will need to complete preliminary calculations that will determine the theoretical amount of the other chemicals needed to perform the titration, in the same fashion as we did with Lab 11.
Look at your notes for Lab 11.
c: You will perform the titration and determine the milligrams of the active ingredient per tablet.
d: I will look over your procedure and preliminary calculations and give you the go ahead to
perform the Lab test.
e: In your Shared Lab group Doc, I expect
In this Lab Test I am require the following:
-
Title Page.
-
Objective.
-
materials
-
a detailed procedure
1) Design of lab – (arbitrary values decided on)
2) Calculations and steps to make certain solutions required in Lab.
3) Steps in the actual lab
-
Data Table
f) typed calculations page that report the milligrams of aspirin per
Tablet the final result. (DO NOT FORGET ANY CHEMICAL
REACTIONS!)
No Background, Results section or Conclusion necessary!
11/20 – Wednesday – Homework
1. Please begin your write-up of Lab 12 based on the requirements posted.
End of Wednesday…
11/21 – Thursday – period 2 –
Lets review the mechanism for the hydrolysis of aspirin:
1. Lab Test Aspirin –
period 3/4-
1. Lab Test Aspirin –
Connections:
The Balancing of complex Redox equations was a skill that was introduced this summer. We are revisiting redox again! It was introduced early in the year to splash you into the course, using voltaic cells (batteries) and electrolytic cells (electrolysis and electroplating). Now we will focus on redox reactions that are NOT part of a electrochemical cell and these complex reactions will make more sense when we balance them with the college method. This method still works for our simple half reactions that we saw in September but will provide more insight on their structure. Most of these complex redox reactions require an acidic or basic environment so it makes sense that I reintroduce them now, after we have studied acid/base concepts.
Most chemical reactions are redox in nature and I want To Do more stoichiometry Labs with redox in the analytical chemistry section of the course.
When you think about it most chemical reactions are either redox, acid/base, or precipitation reactions and through our work together we have studied all three since September.
Redox:
3 Mn+2 (aq) + CrO7-2 (aq) + 2H+(aq) —–> 3MnO2 (s) + 2Cr+3 (aq) + H2O (l)
precipitate
Acid Base:
NH3 (aq) + CO2 (aq) + H2O (l) —-> HCO3-1 (aq) + NH4+ (aq)
base acid base
Precipitation Reaction:
Ca+2 (aq) + CO3 -2 (aq) —–> CaCO3 (s)
precipitate
Now most reactions are one of these three types but as you can see above sometimes these reactions are a combination of each other. Notice that in the Redox reaction we have protons H+ (acid/base) and in the example above a precipitate ( MnO2 (s) ) is made. Redox reactions can also occur in Basic conditions as well.
Your homework will include balancing redox reactions in acidic and basic solutions. Why? Remember that protons produced by acids will pull electrons from chemical species that will spontaneously lose (oxidize) or AND hydroxides produced by bases will push its electrons onto chemical species that will spontaneously accept (reduce) them. The acid/base component of the complex redox equation that we will balance tonight is required to drive these reactions to completion. In order to use stoichiometry we need reactions to be driven forward till the limiting reactant runs out! We need to stay way from equilibrium!
ALSO the first 2 steps of the hydrolysis of aspirin is actually a redox reaction catalyzed by the presence of a the hydroxide ion!!!! Protons (H+) also catalyze these complex redox reactions and so we will learn (review from the summer) how to balance these advanced redox reactions in the presence of Acid or Base!!
11/21 – Thursday Homework:
1. Please read the connections above.
2. Please complete side 1 and 2 (questions 1 – 5) of the Redox 3 balancing redox equations.pdf worksheet and review with the key.
3. You will need to view the How to balance redox reaction in acid environment (College version) lecture for reactions 1 – 3 and How to balance redox reaction in basic environment for question 4.
Please use the key below to help review the homework, especially reaction 5.
Notes on how to balance complex reactions in acidic and basic solutions:
How to balance redox reaction in acid environment (College version) Lecture:
Questions 1 – 3 reviewed.
How to balance redox reaction in basic environment (College version) Lecture:
Question 4 reviewed.
End of Thursday…
11/22 – Friday – period 2/3
1. Lab 13 – Aspirin Test – Last period for data collection
Complete the write-up
period 4 –
1. Lab 13 – Aspirin Test – Last 2 period for data collection
11/22 – Friday – Homework. (Please read all 3 parts.)
1. Lab 11 – TUMS Lab should be completed for me to grade this weekend.
2. Lab 12 TEST- Please complete the Aspirin Lab – lab write-up requirements are posted under
Wednesday above. This will count as a test grade and a lab grade!
– For those groups that did not complete the data collection Friday, please email me with your work (screenshot) so that I can review. You will need to come in Monday in extra help to complete.
I understand that Lab 11 and Lab 12 are challenging to put all the concepts and moving parts together. Please do not feel that you are not getting it as fast as you should. All I care about is that you actually get it. This is not a sprint but a slow steady marathon (ran at a slower pace than Ashley)! Students that I have had in the past and that are currently in decent colleges struggled to get these labs. You will get it as they did and through the struggle you are building knowledge that will last beyond the spring.
Here is a email from past student from an Ok college that I received this fall:
First of all Adam was very gracious in complimenting me but HE DID THE WORK AND HE FOUGHT TO UNDERSTAND! All I did was lay out the game plan and provided help when necessary. SO keep FIGHTING and it will come!!!
Please see me with any questions!
We will build on the concepts of balancing complex redox reactions in acidic or basic environments with the following previously released AP Question from 2010. I gave this out over the summer in the redox module and most of you were blown away with it. It is amazing how for you all have come in very short time and I am sure that you will understand a lot more of this now.
3. Please complete the following released AP problem with we using the video below:
An older key but it will do the trick:
Stiochiometry 7 – 2010B.pdf video:
End of week 3!