## Concentrations and the K value.

Noe BM 1J
Posts: 50
Joined: Sat Sep 07, 2019 12:17 am

### Concentrations and the K value.

Does anyone know the reason as to why the coefficients in a reaction become the exponents of the concentration values?

dtolentino1E
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

### Re: Concentrations and the K value.

I think it's because the coefficients in the reaction are representative of the molar ratio in the reaction, and the K value is basically a ration of the products/reactants by their concentration

WesleyWu_1C
Posts: 117
Joined: Thu Jul 25, 2019 12:16 am

### Re: Concentrations and the K value.

The way I explain it to myself is that these stoichiometric coefficients are just telling us more than one of these species was formed. For example, in the balanced chemical equation to form water, 2H2 + O2 <-> 2H2O, the equation is telling us that two H2O species were created. Another way of writing this equation is H2 + H2 +O2 <-> H2O +H2O. If you take the equilibrium constant for this equation you ([H2O]x[H2O]) / ([H2]x[H2]x[O2]), which simplifies to ([H2O]^2) / ([H2]^2 x [O2]).

I hope this explanation helps.

chari_maya 3B
Posts: 108
Joined: Sat Sep 07, 2019 12:18 am

### Re: Concentrations and the K value.

So is this why when the amount of reactant is increased, K remains the same for the reaction?

Sue Bin Park 2I
Posts: 52
Joined: Mon Jun 17, 2019 7:24 am

### Re: Concentrations and the K value.

chari_maya 3B wrote:So is this why when the amount of reactant is increased, K remains the same for the reaction?

i don't think this has to do with why K remains unchanged.

the eq constant just describes the behavior of a reaction, no matter the amounts of reactants or products you have in your given situation. the value of k defines a specific ratio of products to reactants that all "versions" or situations of the reaction have to adhere to (when they are at equilibrium). your specific given situation involving your unique amount of reactant has no influence on k; rather it's k that determines how those amounts change to achieve equilibrium.

tldr; nope, thats not why.

sarahartzell1A
Posts: 56
Joined: Fri Sep 28, 2018 12:17 am

### Re: Concentrations and the K value.

Maybe because it represents the molar ratio of the substances.

Noe BM 1J
Posts: 50
Joined: Sat Sep 07, 2019 12:17 am

### Re: Concentrations and the K value.

This definitely makes sense!!! Thanks.

WesleyWu_1C wrote:The way I explain it to myself is that these stoichiometric coefficients are just telling us more than one of these species was formed. For example, in the balanced chemical equation to form water, 2H2 + O2 <-> 2H2O, the equation is telling us that two H2O species were created. Another way of writing this equation is H2 + H2 +O2 <-> H2O +H2O. If you take the equilibrium constant for this equation you ([H2O]x[H2O]) / ([H2]x[H2]x[O2]), which simplifies to ([H2O]^2) / ([H2]^2 x [O2]).

I hope this explanation helps.

805422680
Posts: 103
Joined: Sat Sep 14, 2019 12:16 am

### Re: Concentrations and the K value.

the stochiometric coefficients show the number of molecules of one type reacting together. therefore, if the equation is 2H20----> H3O+ + OH-, two water molecules react to give one H3O+ molecule and one OH- molecule. concentrations of products are multiplied and divided by reactants to the give the Kc value. therefore, if you think of the equation as H2O + H2O----> H3O+ + OH-, the use of powers will make more sense to you.

Return to “Equilibrium Constants & Calculating Concentrations”

### Who is online

Users browsing this forum: No registered users and 3 guests