Writing Equilibrium Expressions

[Diana Sandoval 1K]

When writing the equilibrium expression does it matter whether we use brackets or parenthesis?

[Krista Mercado 1B]

Yes, brackets are used specifically in equilibrium expressions to indicate the concentration of a certain substance.

[Danny Elias Dis 1E]

Brackets are used when you are calculating Kc and parentheses are used when you are calculating Kp. You also need to include a P next to each reactant and product when calculating Kp to indicate you are using the partial pressures of each compound. Brackets indicate concentrations.

[Jake Gordon 1A]

I agree with the students that brackets is the most proper way to indicate concentration. Also it can be useful to use parenthesis after the numbers have been substituted in in order to avoid confusion. An example would be

[O3]^2 / [O2]^3 when the numbers are inputted (.1)^2 / (.2)^3

It is not necessary but I think it helps in the thought process moving from concentrations of gases or solutions to computing actual numbers. In all reality you can use brackets or parenthesis as long as you arrive at the right answer. I hope this answers your question.