Hydrogen peroxide decompose to oxygen.......?

Question

Does the amount of concentration of hydrogen peroxide affect the speed at which oxygen is produced??
And how could I prove this in an experiment?
txs

Answer 1

Wikipedia has this information on hydrogen peroxide:

"Hydrogen peroxide always decomposes (disproportionates) exothermically into water and oxygen gas spontaneously:

2 H2O2 → 2 H2O + O2

"This process is very favorable; it has a ΔHo of −98.2 kJ·mol−1 and a ΔGo of −119.2 kJ·mol−1 and a ΔS of 70.5 J·mol−1·K−1. 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."



So H2O2 decomposes to oxygen and water. The rate of decomposition depends on temperature, concentration of H2O2, pH, and other factors that include:

- catalytic trace of cation
- elements of univalence or more such as Fe, Cu, Ni, Cr, Pb and Mn
- active Surface : Especially for rough surfaces
- suspended Matter : Dust Particle
- pH : decomposition accelerates in alkaline condition.
- radiation - especially the ray of short wavelength(about 300A)

This list of other factors is from:
http://www.dcchem.co.kr/english/product/p_basic/p_basic14.htm


Measuring the oxygen evolved over time would be the easiest way.

Run tubing from the top of a bottle of H2O2 and let it bubble into an inverted test tube filled with water. Measure the O2 formed as a function of time.

Answer 2

Concentration is a factor in a chemical reaction but it shouldn't be an issue in decomposition...the speed of decomposition is related to the factor that is making the molecule decompose for example U.V. radiation or catalase enzyme or heat.

To make an experiment that could prove this i think the best solution is to prepare a solution of hydrogen peroxide (IMP. keep the solution in the dark...cover with foil and dim down the light). It is also important to keep other factors like temperature stable example put it in a water bath!!...obviously this is not very effective or else you can cool the solution to 0 degrees and add ice cubes made of distilled or even better deionised water) Prepare different concentrations of the H2O2 solution. Then expose the solutions to UV and with the use of a closed system with a gas syringe, take readings every second. Its important to keep the UV intensity and wavelenght the same in each tentative. Even though the final volumes would be differnt it doesn't matter since you are only interested in the rate at which oxygen is evolved!!

Maybe experimentally it would give some errors but think of this in this way...

If you have two molecules and only one U.V. ray (able only to break down one molecule) is made to hit the molecule only one decomposes, if on the other hand you have 50 molecules in the same space and one U.V. ray is made to hit the molecules...only one will decompose...

So theoretically...concentration shouldn't play a role in the rate of evolution of oxygen!!!

Answer 3

Hydrogen Peroxide is H202 which means it is already 2 parts oxygen. HP is used in hairdressing as a means of imparting colour into hair or to remove colour molecules from the hair. The higher the concentration - the faster this process works. You could experiment by timing the oxygenation process (ie how long it takes dark hair to lighten and which concentration yields the best results).

I've just read Oracle2Worlds answer and now I feel inadequate!!!


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Answer 4

Yes higher the concentration greater will be the oxygen decomposition. Usually H2O2 is stabilised by using some stabilisers like acetanilide.
But you can very well check it by taking Cr metal complexes in equal quantity for equal amoun of H2O2 but different concentrations which will decompose the H2O2 in oxygen. Now you can either collect the liberated oxygen and find out.

Answer 5

Yes it does. The greater the concentration of hydrogen peroxide, the faster it will decompose.

However, the best way and quickest way to make it decompose is using manganese oxide as a catalyst.

Answer 6

It decomposes to oxygen and water. So, you could measure the water produced, or the oxygen produced, or both. Also, the concentration must affect it, because of the energy required to dissolve the bonds.