EXPERIMENTAL: AN INVESTIGATION OF SOME OF THE VARIABLES INVOLVED IN
THE DECOMPOSITION OF AQUEOUS HYDROGEN PEROXIDE

Introduction
Hydrogen peroxide is a toxic excretion product from certain metabolic
reactions in living cells; accordingly, its removal is essential to
ensure survival of a living cell or an organism.

Aqueous hydrogen peroxide decomposes slowly at ambient temperatures,
but published studies have shown that its decomposition is speeded up
by the enzyme catalase and by various inorganic catalysts [such as
manganese(IV) oxide]:    Catalase or MnO2
               2H2O2(aq) 覧覧覧覧覧覧覧覧ｮ 2H2O(l) + O2(g)

In this investigation, you are required to examine at least three
variables involved in the decomposition of aqueous hydrogen peroxide;
at least two of these must be quantitative.

Notes
1.  Each enzyme is assigned a numerical classification (as approved by
the international scientific organizations); catalase, for example, is
E.C. (Enzyme Commission) 1.11.1.6.

2.  Despite differences in size and complexity, all living organisms
show remarkable similarity in biochemical reactions; and so, as might
be expected, catalase is present in most of these organisms.  However,
extraction of the pure enzyme is tedious - so most investigations use
convenient sources (e.g., liver, potato, or yeast).

3.  Apart from your notes and standard textbooks, sources of scientific
knowledge include encyclopaedias in libraries, on CD-ROMs, and on the
Web; it is good practice to include a bibliography in your write-up.

4.  You are provided with 30% aqueous hydrogen peroxide, sources of the
enzyme catalase (e.g., potato), a variety of inorganic substances, and
distilled water.  In addition, you will need to use - within reason -
suitable apparatus.

5.  The proposed plans of your investigation should be presented in
detail; these plans may be modified as the investigation proceeds.

Dr. R. Peters                  Next                      Contents' List