### Calculating Kc

Posted:

**Fri Jan 11, 2019 11:41 pm**Can someone please explain to me why it’s necessary to balance a reaction equation when calculating Kc? I don’t understand why it mattters if concentration changes dont affect Kc.

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=49&t=39713

Page **1** of **1**

Posted: **Fri Jan 11, 2019 11:41 pm**

Can someone please explain to me why it’s necessary to balance a reaction equation when calculating Kc? I don’t understand why it mattters if concentration changes dont affect Kc.

Posted: **Fri Jan 11, 2019 11:44 pm**

The chemical equation needs to be balanced becasue in the equilibrium equation, each species is raised to the power of its stoichiometric coefficient (which is obtained from the balanced chemical equation).

Posted: **Sat Jan 12, 2019 12:01 am**

Though the concentrations don't affect Kc, the coefficients in a balanced equation are needed to calculate the equilibrium constant. You need to raise the concentrations to the power of how many mols are in the reaction.

Posted: **Sat Jan 12, 2019 8:58 am**

Blanking an equation gives you the correct stoichiometric values for the equation. This is important because you have to raise the concentration of a species to its stoichiometric concentration to get the correct Kc

Posted: **Sat Jan 12, 2019 9:38 am**

Using the balanced equation is imperative because the stoichiometric coefficients are needed in order to solve for KC as they are what you raise each concentration to the power of. Therefore you need the correct balanced ratio for each reaction and the stoichiometric coefficients are necessary.