Only a specific fraction of all total collisions cause chemical changes called fruitful collision. The fruitful collisions have enough energy at the moment of impact to break the existing bonds and form new bonds. This will cause the H-O bonds in the hydrogen peroxide to break down leaving water (O²) and produce Oxygen (H²O) This process has a ΔHo of −98.2 kJ/mol and a ΔGo of −119.2 kJ/mol. This is the symbol equation of the reaction producing oxygen:
2 H2O2 → 2 H2O + O2 + Energy
The rate of decomposition is dependent on the temperature and concentration of the peroxide, as well as the pH and the presence of impurities and stabilizers.
From further research I have found out that a reaction occurs on a solid’s surface. Therefore the particles inside the solids will not react until the particles on the surface have reacted and moved away.
So, the longer catalyse is kept in the hydrogen peroxide, the more oxygen produced, as there are more collisions of particles. Based on these reasons I predict that as the number of 1cm³ cubes increases, there will be more fruitful collisions resulting in a faster rate of reaction. However, as time increases the reaction on each surface area will start to slow down.
Enzymes are a particular kind of protein that have the ability to catalyze reactions in living organisms. Proteins are very long chain molecules made up of amino acid building blocks. The protein chain is folded in a complex three dimensional shape known as its tertiary structure. The chain is held in this shape by interactions between different parts of the chain. They are biological catalysts, which speed up the rate of chemical reactions. The functioning of enzymes is affected by temperature and the ph of the solution. The rate of reaction of enzyme and substrate increases with the increase of temperature up to a optimum of 40*C. Beyond this point, the rate of reaction decreases.
Enzymes Potato cells contain an enzyme called catalyse, it speeds up the breakdown of hydrogen peroxide into water and oxygen
The enzyme being used in this experiment is catalase. Hydrogen peroxide is formed as a waste product of metabolism in many living organisms. It is toxic and must be quickly converted into other, less dangerous, chemicals. To manage this problem, the enzyme catalase is frequently used to rapidly catalyse the decomposition of hydrogen peroxide into harmless oxygen and water. Catalase is also used in the textile industry, removing hydrogen peroxide from fabrics to make sure the material is peroxide free. A minor use is in contact lens hygiene, some lens cleaning systems sterilize the lenses by soaking them in a hydrogen peroxide solution, and catalase is used to decompose the peroxide before reinserting the lenses in the eye.
Catalase is an enzyme present in living cells. Potatoes are going to be used as they contain catalase enzyme, within their cells. The substrate on which the catalyse shall work on is Hydrogen Peroxide producing oxygen and water.
Factors:
The Rate at which a chemical reaction takes place can be affected by certain factors:
- Concentration of reactant:
If the concentration of any reactant in a solution is increased, the rate of reaction is increased. This is as increasing concentration increases the number of successful collisions between the substrate and solid.
So above it can be seen that Fig 1.2 has more concentrated acid particles than Fig 1.1 so there is more fruitful collisions resulting in an increase in the speed of product formation.
