19 Mar 2020

Job's Method - The Covid-19 Version

Lab Experiment

Submitted by Chip Nataro, Lafayette College

This is the classic Job's Method experiment from "Synthesis and Technique in Inorganic Chemistry" 2nd Ed. (1977 or 1986 pp 108-114) by R. J. Angelici. There are slight changes from the experiment published in the book but they just include running solutions with ethylenediamine mole fractions of 0.67 and 0.75, so details will not be provided. What is provided are a series of pictures and videos showing the experiment being performed. Also included are the raw files of the absorbance spectra in EXCEL. It is not perfect but given the situation many of us are facing at the time this is published, it is better than nothing.Note that this lab was updated on 4/4/2020. The previous data was terrible. New solutions using a fresh bottle of ethylenediamine were prepared. The two solutions mentioned previously were also included. The data is much better. The worked up data has also been included in the instructor only files.

My apologies to my coauthors who spent way too much time looking over the original data set and trying to make sense of it. Their thoughts and insight led to this update. My sincere apologies to anyone else that scuffled over the original data.

Learning Goals: 

A student should get an appreciation for what doing this lab would be like by watching videos. In addition, the student will analyze the data provided and determine the species present in solutions containing various mole fractions of ethylenediamine and Ni(II).

Equipment needs: 


Implementation Notes: 

Like most everyone at this time this is going to be a trial by fire.

Evaluation Methods: 

Students are generally asked to write a full lab report including an abstract, brief introduction, experimental and results/discussion. I will likely not ask them to do that in this virtual lab. However, they will be asked to determine the value for n for the various [Ni(en)x] solutions as well as questions 1 and 2 from Angelici's book. In addition, I typically ask them to do some literature searching questions, but I am not sure if they will have access to SciFinder so I may have to bypass that or provide them the original papers I have them look at. Links to those papers are included.

Evaluation Results: 

I'll use this in a few weeks and see how it goes.

Creative Commons License: 
Creative Commons Licence


Quick note: this experiment is not in the 3rd edition of Angelici. The pages given are correct for the 2nd edition, published in 1977 (and it is also in the first).

We ran this lab as an online / virtual lab for second semester general chemistry.  The data are great now!  Thanks, Chip!


I would predict that my students might say that the lab was a bit complicated.  I had a pre-lab assignment for them to do, then I released the data to them after that was done.  Everything was especialy complex because of the new online / virtual environment.  So I think students who ran into questions felt especially marooned, even though we were running lab through zoom and there were opportunities to ask quesitons.  It just gets crazy with 24 people on zoom at once, even with effective use of breakout rooms.


So all in all, it was great to have these data to work wtih and such a nice series of photos!  I even learned a new technique as I watched Chip make the nickel sulfate solution.

Hmmm, the 1986 edition I use must be a reprint of the 2nd edition. The first edition of this book was published in 1969 and the review from J. Chem. Ed. can be found here. The second edition was released in 1977 with the review here

Probably. I am seeing some mid 80s dates on Amazon for the 2nd, but those are probably print dates not publication dates. The 3rd edition came out late 90s and has two coauthors added (and a different publisher).I somehow have all three editions in my office. I also have a copy of Marusak "integrated approach to coord chem". They cite the 3rd edition, probably because the person putting together the bibliography thought it should always be the most recent edition, but they only have Angelici as the author, but the first author had changed to Girolami in the 3rd edition. This authorship changing for a book reminds me of Shriver and Atkins over the years, or Lehninger's  Biochemistry.


However, the most interesting citation I found this week was in Wikipedia. The entry for Job plot had a huge typo in the reference to Job's 1928 paper. Wrong journal, and the error was there for ten years.  I fixed this (and put a note in the Talk page).  But in my attempt to find the paper I discovered a few citations in the current literature using the incorrect reference. Chemical Abstracts had the right reference, or close to it (the journal name changes a bit over the years). But then I realized that not every institution in the world has a subscription to CAS (and some people are... in a hurry when they write a paper). I also suspect very few people citing Job actually read more than the abstract (if even that!).


I'll wait until libraries have their staff back and submit an ILL for Job's paper. It may have already been scanned somewhere but if not then a request now wouldn't be fulfilled for quite a while.

Ugh, If only I had a more valid reason to run into the office, I have all of the different versions. My last valid excuse to go in was when our instrument specialist was doing a N2 (l) fill on our NMR and he notice my lab was 96o! We still don't know why.

Well what do you know. The 2nd Ed. had two different runs with two different publishers. It was initially published in 1977 as a hardcover by W.B. Saunders. Then in 1986 it was republished as a paperback by University Science Books. But it is identical in terms of page numbers. I never realized that. I will update the LO.

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