Useful
links for chemistry
Internet
sources have been, for the most part, confined to
a few reactions – thiosulphate and hydrochloric
acid and the iodine clock. The Regensburg
University web-site, however offers a range of
different experiments, including ester
saponification and hydrolysis. The procedures for
the SN1 and SN2 hydrolysis of alkyl halides and
enzyme kinetics may easily be modified for use
with data logging systems available in Britain.
The texts are in English and the translation
falters only occasionally, but compounds are
usually referred to by “traditional” names
rather than the IUPAC ones. The experiments come
with varying amounts of background theory, an
outline procedure and extensive sample data and
spreadsheet illustrations – the index page to
this very useful collection is to be found at –
www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/indexe.html.
(NB There is an underline character between
Organische_ Chemie.)
The
kinetics of oxidation of bromocresol green by
sodium hypochlorite is presented at www.nsm.smcm.edu/Chemistry/chem-gchemlab/WebLab/ExptSplit/LAB14-1TR.htm
with an extensive background discussion.
The
behaviour of catalase, extracted from turnip,
horseradish or potato, is investigated at www.mhhe.com/biosci/genbio/dolphin52/topic5.html.
A detailed description of the preparation of the
reagents is given but the experimental procedure
is limited to a few suggestions and no sample data
are given. Whilst this might be frustrating for a
teacher looking for an experimental procedure to
demonstrate the characteristics of enzyme
kinetics, it is on the other hand, an excellent
starting point for a student investigation.
The
substitution reaction involving iodine and
propanone appears on many web pages but www.dartmouth.edu/~chemlab/chem6/kinet1/full_text/procedure.html
proposes the use of cyclohexanone as an
alternative ketone. It is important to remember
that plastic cuvettes may not be inert to
solutions containing ketones and may also become
stained if iodine solutions are left in them for
more than a few minutes.
An
interesting investigation into water quality
monitoring is described on the web-site
departments.oxy.edu/tops/Waterquality/waterstudent1.htm
in which baker’s yeast and diluted
milk are used as a model for the bio-remediation
of polluted waters. This web-page comprises part
III of the experiment, giving an introduction and
a comprehensive procedure, together with some
questions to be answered on the basis of the
results obtained.
A
clock procedure is used to study relative rates of
hydrolysis of alkyl halides on web.uccs.edu/bgaddis/leadership/expt9_1D4.htm
. There are no sample data but the experimental
directions are clear and there is an excellent
summary of the relevant background, together with
a post-lab assignment of nine questions to be
answered on the basis of the results obtained.
A
useful manual of experiments involving the use of
a simple fuel cell is located at www.ectechnic.co.uk/exps.html
- experimental details are very basic but there
are useful references to other internet sites.
A
purely theoretical web-site at server.chem.ufl.edu/~itl/2041/lec_m.html
has some very attractive graphics to illustrate
the temperature dependence of reaction rates.
Further useful guides occur at www.chemguide.co.uk/mechmenu.html
- this is the menu page for some excellent
material on organic mechanisms pitched at GCE A
Level pupils – and www.ksw.org.uk/departments/chemistry/sn2.html
has a useful summary of Nucleophilic Substitution.
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Vernier Catalogue 
