Investigation into Rates of Reaction when Concentration is changed.

Investigation into Rates of Reaction when Concentration is changed

In this investigation, I will try to work out what concentration a reaction takes place in fastest; a highly concentrated solution or a highly dilute solution.

2H2O2 2H2O + O2

In this experiment we need to use Hydrogen Peroxide, a chemical in a liquid state which is similar in structure to water (Hydrogen Peroxide being H2O2, just one more oxygen atom than a water molecule). Hydrogen Peroxide normally decomposes very slowly over a long period of time; however, when added with Manganese Oxide whilst the Hydrogen Peroxide is in air or water, the reaction instantly speeds up. The reaction is based upon the collision theory; the rate of reaction depends on how often and how hard collisions of particles take place. The catalyst works by providing a surface which the reacting particles can stick on to. They can then collide easier with each other once they are on or going toward the surface.

Enzymes are the catalyst of all living beings, as they are produced in living things. Enzymes help chemical processes in a living organism happen faster, and a way to speed them up with the enzyme is by raising the temperature of the body. Enzymes do work better in warm conditions, but they work at their peak in a small range of temperatures, and if the temperature were to go too low or too high, then the enzymes would slowly dysfunction and die. That is a main reason why our body temperatures are kept at a certain point. Now enzymes are being used more and more instead of non-biological catalysts as they are running out (e.g. some metals such as Platinum) and there are various enzymes for different uses (as said in the CGP revision guide to chemistry, an apple turns brown when cut due to a particular enzyme).

Activation energy is the minimum amount of energy need for reactant particles to collide and react together, and it is measured in kilo joules (kJ). Faster reactions, like those with a catalyst, have a lower activation energy. In the example of a catalyst, this is because the catalyst causes the minimum amount of energy to decrease, so more reactions could occur at its current amount of kJ. The difference in the minimum amount of energy needed is shown in the graph below.

A reaction occurs when two different particles collide against each other. The faster, harder and higher in amount of collisions there are, the faster the reaction will occur. The rates of a reaction can be made to be faster or slower depending on certain factors that affect the speed or the distance between the atoms.

The Temperature of the substance – When the temperature of the solution of reacting particles are increased, the particles will move quicker, so there is a higher chance of them colliding

Using a catalyst – As mentioned above, the catalyst gives the particles a surface to stick to so they can collide easier.

Using an enzyme (biological catalyst) – Basically the same as a catalyst, only this is biologically produced so it can never run out so long as there are living things.

Increasing the concentration in the substance – This occurs in a solution, and means that when ...