<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">Hi all, especially Mike.<br>
<br>
I am not that unhappy about the lack of numerical approaches in
buffering. The type of rate calculations that I mentioned in my
past post are way too complex for even 1st year Uni.<br>
<br>
I would like a bit more emphasis on linking pKa and pH,
particularly the equation pH = pKa + log [H+][A-]/HA which
predicts that an equimolar concentration of acid/conjugate base
will have a pH that is set by the strength of its ionisation
constant. This is incredibly predictive, and allows you to chose
an appropriate buffer system for any situation you need. It also
explains why we tell our kids that buffers only really work within
1 pH unit of pKa. It is also a simple, low hanging fruit.<br>
<br>
pKa's are not explicitly in the curriculum, (although they appear
in the Nelson book, and are worthwhile given we have taught pH).<br>
<br>
We always have this tussle between rigor and relevance. Now it
seems that there is a tend to pursue rigor. Although note: by
labelling any dingy dry dank collection of factoids rigorous, you
can persuade people to over-pack their curricula. Many people
(myself includes) feel that the SHE aspects of our current courses
have not been well done, and have led to little improvement in
student understanding at WACE level. The danger with this is that
calling for that kind of SHE reform may lead to incredibly turgid,
"math monkey" - favouring curricular that divert students with the
potential to be quite creative, innovative and successful chemists
from the course. I have seen more than on struggling student,
sitting in the high 60s, blossom into gifted chemists at
university. I also know a number of straight A chemistry students
who know next to nothing about chemistry, 5 years plus out from
the last exam. The important thing is to ensure that faux "rigor"
dousn't choke our courses. Also to make sure that we don't get
"committee rigor", where everybody's pet area gets incorporated
and the whole thing becomes unteachable, and joyless to learn.<br>
<br>
My personal preference would be to teach in depth some chemistry
that can be a template for future efforts. Such would include a
really good separation (getting an antibiotic out of a broth, or
perhaps citric acid from culture on cornsteep licquor), a good
organic synthesis (preferably 4 or 5 steps, plus work up),
managing and remediating an algal bloom, gold separation, wine
chemistry, etc. It isn't SHE, but it is where I would have liked
to see it go. But focus on the processes, then bring in societal
stuff and people, as a sideline. If you want to see how this is
done well, albeit at a simpler level, check out the RSC's
Chemistry In Its Element series. <br>
<br>
As to the textbooks: If it ain't in the curriculum, a textbook
includes it at its great peril. I think the lamentable state of
textbooks relates more to the curriculum design process. Look at
the curriculum guidelines - they are vague crap statements,
designed to comply with an ideological/theoretical model that is
unviable in a production environment such as a school. You can't
jump onto the textbook writers because, they like us, are just
trying to read the tea leaves. Nevertheless, I know the sense of
anger at using a poorly written and factually incorrect textbook.
There just isn't the advance notice of new content, and there
isn't the proper multi-level review of textbook, teacher materials
and sample texts. Worse, there isn't time for those skilled in
schools to deploy their talents to fix it - when was the last
working year you had when you averaged under 45h a week? 1988
wasn't it?<br>
<br>
Have a nice weekend! I am going frog watching!<br>
<br>
Cheers,<br>
Leon<br>
<br>
On 19/05/2017 4:12 PM, Michael McGarry wrote:<br>
</div>
<blockquote
cite="mid:95E2FBA9-46F9-4B91-B579-71E382C47904@gmail.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<p class="MsoNormal"><span style="font-size: 14px;" class="">Greetings
Science Colleagues,</span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">“Buffer
solutions are conjugate in nature and resist changes
in pH when small amounts of strong acid or base are added to
the solution; buffering
capacity can be explained<b class=""> qualitatively</b>;
Le Châtelier’s Principle can be applied to predict how
buffers respond to the
addition of hydrogen ions and hydroxide ions.” [Page 12]</span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">Reference:
SCSA WACE ATAR URL: <a moz-do-not-send="true"
href="http://wace1516.scsa.wa.edu.au/__data/assets/pdf_file/0012/10605/Chemistry-Y12-Syllabus-AC-ATAR-GD.pdf"
class="">http://wace1516.scsa.wa.edu.au/__data/assets/pdf_file/0012/10605/Chemistry-Y12-Syllabus-AC-ATAR-GD.pdf</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">A
recent post to STAWA’s CATALIST e-forum motivated me to ask
these
two Questions.</span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">Question
1: Would a significant proportion of Australian Year
12 secondary chemistry students have the mathematical skills
to be able to
satisfactory explain <b class="">quantitatively</b> buffering
capacity?</span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">Question
2: Do the commercially available Year 12 Chemistry
textbooks written for the SCSA WACE ATAR Year 12 Chemistry
syllabus include a
text section that explains <b class="">quantitatively</b>
buffering capacity?</span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><b style="font-size: 14px;" class="">Useful
URL’s on
Buffer Solutions</b></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
1: <a moz-do-not-send="true"
href="http://www.mhhe.com/physsci/chemistry/chang7/ssg/chap16_2sg.html"
class="">http://www.mhhe.com/physsci/chemistry/chang7/ssg/chap16_2sg.html</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
2: <a moz-do-not-send="true"
href="https://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/Buffers.htm"
class="">https://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/Buffers.htm</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
3: <a moz-do-not-send="true"
href="http://scifun.chem.wisc.edu/CHEMWEEK/BioBuff/BioBuffers.html"
class="">http://scifun.chem.wisc.edu/CHEMWEEK/BioBuff/BioBuffers.html</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
4: <a moz-do-not-send="true"
href="https://www.rose-hulman.edu/%7Ebrandt/Chem330/pH_and_Buffers.pdf"
class="">https://www.rose-hulman.edu/~brandt/Chem330/pH_and_Buffers.pdf</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
5: <a moz-do-not-send="true"
href="http://virtuallaboratory.colorado.edu/CLUE-Chemistry/chapters/chapter9txt-2.html"
class="">http://virtuallaboratory.colorado.edu/CLUE-Chemistry/chapters/chapter9txt-2.html</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
6: <a moz-do-not-send="true"
href="https://www.chem.purdue.edu/courses/chm333/Spring%202013/Lectures/Spring%202013%20Lecture%205.pdf"
class="">https://www.chem.purdue.edu/courses/chm333/Spring%202013/Lectures/Spring%202013%20Lecture%205.pdf</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
7: <a moz-do-not-send="true"
href="http://www.ulm.edu/chemistry/courses/manuals/chem1010/experiment_09.pdf"
class="">http://www.ulm.edu/chemistry/courses/manuals/chem1010/experiment_09.pdf</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">URL
8: <a moz-do-not-send="true"
href="https://www.une.edu.au/__data/assets/pdf_file/0003/121728/chemistry-teacher-notes-answers.pdf"
class="">https://www.une.edu.au/__data/assets/pdf_file/0003/121728/chemistry-teacher-notes-answers.pdf</a></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">Best
Wishes,</span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class=""><o:p
class=""></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 14px;" class="">Michael
John McGarry</span></p>
<p class="MsoNormal"><o:p class=""></o:p></p>
<!--EndFragment-->
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Catalist mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Catalist@lists.stawa.net">Catalist@lists.stawa.net</a>
<a class="moz-txt-link-freetext" href="http://lists.stawa.net/mailman/listinfo/catalist_lists.stawa.net">http://lists.stawa.net/mailman/listinfo/catalist_lists.stawa.net</a>
</pre>
</blockquote>
<p><br>
</p>
</body>
</html>