Investigation into the decomposition of hydrogen peroxide.

Biology Coursework

Biology Coursework-Investigating into the decomposition of hydrogen peroxide.

Introduction

I am investigating into how a certain factor alters the rate of decomposition in hydrogen peroxide. When yeast is mixed with hydrogen peroxide, bubbles of oxygen are produced. This is because hydrogen peroxide has been broken down into water and oxygen through a chemical reaction known as decomposition.

The equation for this is:

Hydrogen peroxide water and oxygen

2H2 O2 2H2O+O2

The rate of the reaction is determined by the enzyme in the yeast, catalase. This is an enzyme, which acts like a catalyst i.e. it speeds up what happens in the reaction; it is never used up in a reaction. In order to measure the speed of the reaction you apply the data to this formula:

Speed of reaction=amount of oxygen made/time.

Variables:

Temperature,
Concentration of enzymes,
Level of hydrogen peroxide.

I will provide a brief explanation into each of the variables below:

Temperature

This variable will affect the rate of decomposition because, as the catalase enzymes in the yeast are heated, the molecules move around more, and collide into one another. Consequently, the hydrogen peroxide begins to decompose quicker. However, if you heat the enzymes beyond a certain point, the rate of decomposition in the hydrogen peroxide will slow to a halt. This is because the enzymes will die and therefore cannot react.

Concentration of enzymes

The concentration of enzymes, in this case-catalase, is directly proportional to the rate of decomposition in the hydrogen peroxide. This is because the more catalyst enzymes there are in the yeast, the quicker the will break down the hydrogen peroxide solution.

Level of Hydrogen Peroxide

This variable will affect the rate of decomposition because, the more hydrogen peroxide there is the harder it will be to decompose as there is more to break down.Consequently, unless the concentration of catalase is also increased it will slow down the reaction.

The variable I have chosen to investigate into is the concentration of the enzymes. This will mean that I will alter the concentration of catalase whilst using water to keep the volume the same overall. So, as I decrease the amount of catalase I will increase the amount of water. Hopefully, this will then mean that I will be able to easily see how the concentration of catalase affects the rate of decomposition.