[ontario314]

Could someone provide me with a detailed explanation as to why increasing the concentration of hydrogen peroxide increases the rate of decomposition. Thanks in advance.

[Arkcon]

Well, for starters,how can you support this observation?

[ontario314]

Well I have seen numerous online lab activities about how concentration of H2O2 increases rate of decomposition. I was just curious about the specific explanation since most don't seem to provide any reasoning.

[Arkcon]

Ohh...awesome.  Would you have a link to one?  I'd like to read it.  Example: A one percent solution loses a half a percent a minute under certain conditions, whereas a three percent solution loses more than half a percent in the sane time under the sane conditions.  The cause of such a synergistic effect, if real, would certainly be interesting.

[Babcock_Hall]

@OP,

Can you explain the difference between a rate and a rate constant for us?

[Arkcon]

Or do you mean something along these lines: www.chemguide.co.uk/physical/basicrates/concentration.html

[Enthalpy]

At least one influence exists for real: above 70% concentration, the produced heat suffices to evaporate the liquid, so the temperature doesn't stop around +100°C, and the decomposition can go boom.

Probably not what was meant here. And anyway, the decomposition depends essentially on impurities and on stabilizers. Comparisons must be difficult.

[ontario314]

Or do you mean something along these lines: www.chemguide.co.uk/physical/basicrates/concentration.html

Yes. So I guess my question is do the hydrogen peroxide molecules collide on their own which doesn't usually produce enough energy to exceed the activation energy, but in the presence of a catalyst do, thus initiating the reaction?

[Corribus]

The O-O single bond is very weak, and the decomposition is thermodynamically favored. However in ideal conditions it is kinetically very slow. The decomposition reaction is actually fairly complicated mechanistically but the easiest way IMO to understand why it is slow is that it violates spin conservation.  I.e., the oxygen produced is not in the singlet state as the starting material is. A variety of catalysts and also UV light can help reduce this kinetic bottleneck, though.