For the reaction 2H2 + O2 -- 2H2O, how do I give an equation for the equilibrium constant in terms of the concentrations of products and reactants involved?

For any reaction, the equilibrium constant is given in the form: K = [products] / [reactants]

Where [ ] is used to denote the concentration of the species. 

Therefore we can substitute in for the molecules given above, which becomes, K = [H2O] / ([H2] x [O2]). 

But, we're not finished there. We have to remember the stoichiometric coefficients given in the balanced equation, and put them to the power of the respective molecules. 

This gives the final, correct answer, K = [H2O]2 / ([H2]2 x [O2]). 

LS

Related Chemistry A Level answers

All answers ▸

i) Write a full balanced equation for (a) the complete combustion of glucose and (b) the incomplete combustion of glucose. ii) Following from part i) suggest a reason (and explain) the difference with the product in reaction (a) and that of reaction (b).


Calculate the relative atomic mass of an atom.


What is a chiral carbon and optical isomerism?


What is the ideal gas equation?