exp 5 (EQW) - pre-lab

[Zellmer, Robert]

Just a reminder, there is a pre-lab for exp 5 (EQW).  It must be completed before
lab or you don't get credit for it.  You'll find it at the same site you found the
notebook exercise and pre-lab and data entry for exp 1 (SCM).

We have not gotten to the material that applies to exp 5.  I want to make
sure you can answer all the questions from just the lab manual.  Contact
me or your TA if you have questions.

The majority of what you need to complete the pre-lab is contained in the
lab manual for exp 5.  You will need an understanding of formula weights,
the "mole" and molar mass.  These are covered in sections 3.3 and 3.4.
For further reading on ionic equations, acids and bases, and neutralization
reactions see sections 4.2 and 4.3.  Dilution is in section 4.5.  We will be
getting to some of this in lecture tomorrow, unfortunately too late for Thursday
labs.  Solution stoichiometry and titrations are covered in section 4.6.   You
should look at this material in the book.  However, you should be able to get
what you need for the pre-lab from the lab manual.

Before attempting the pre-lab you should read the Discussion section
and review the calculations.  Write the procedure so you have some
idea where the numbers are coming from. You can watch the video in
the pre-lab w/o answering any questions and then get out of the pre-lab.
It won't even register as having been done.  It will give you a better idea
of what's going on so the procedure makes sense.  You will have to
rewatch it when you actually do the pre-lab.  The procedure MUST
be written in your own words in an outline form similar to my example
on the last page of the syllabus (and found at a link <http://chemistry.osu.edu/%7Erzellmer/chem1250/lab/notebook_proc_1250.pdf> on my class web
page).  Pay attention to the equations and the examples in the manual
since the calculations you'll be doing are very similar.

In Part A of the exp you'll be using something with an acronym of KHP.
People often mistakenly think KHP is potassium hydrogen phosphorus.
It is NOT.  KHP is an acronym for potassium hydrogen phthalate,
KHC8H4O4.  It is a salt consisting of K+ and HC8H4O4-.  The latter
is a weak monoprotic acid (hydrogen phthalate).  This is discussed in
the lab manual in the Discussion and Lab Procedure sections of the
manual (pages 24-28).

The link for the pre-lab is in the syllabus, on Carmen and my web page
so  if the following doesn't seem to work from your e-mail you can find
it somewhere.

https://uglabs.cbc.osu.edu/1250/pre-postlabs.php

This will take you directly to the main Chem 1250 pre and post-lab page.
READ this page and the Terms and Conditions of Use at the top if you
didn't do it already.  I've sent instructions for how to use this in a previous
e-mail.  Remember, if you start again for any reason you have to watch
the video again and answer all the questions again.

Once you click on the pre-lab or data-entry links you'll get a new screen.
There is an INSTRUCTIONS button in a red box toward the upper-left of
the page.  Click on it before you start.  Pay attention to what it's telling you
to do in terms of units, how to enter the numbers, etc.

The pre-lab essentially consists of two parts.  The first part starts with
a video, which you need to watch all the way through (including the
credits) or you will have points deducted.  Just let it run until it stops on
it's own.  Don't move on to the next question until it stops.  Then there is
a series of questions dealing with the discussion and procedure in the
manual and the video.

Below this part is the data-entry part of the pre-lab. You'll be given
numbers similar to what you'll obtain in the actual experiment. You will
then do the appropriate calculations and enter the numbers (make sure
you have the correct sig. fig.).  That's pretty much it.

When you are finished and satisfied with your answers click on the Submit
button at the bottom.  The program will send you an e-mail if the pre-lab
was submitted correctly.  Also, the screen should refresh with your entries
and results and score.  If it doesn't, it didn't submit properly.

Dr. Zellmer

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osu.edu/pipermail/cbc-chem1250/attachments/20220126/ac00f333/attachment-0001.html>