Calculating the Reaction Quotient

[Nathaniel 2E]

Calculate the reaction quotient, QC, from the following equilibrium data collected in a 3.00 L sealed reaction vessel for the reaction: AsH3 (g) ⇌ As (s) + H2 (g)
AsH3 = 5.55 x 10-4 mol, As = 3.31 x 10-3 mol, H2 = 1.23 x 10-3 mol.

This is from the second module, I keep messing up and not arriving at the right answer. Do I use the QC equation of Products/Reactants? Do I have to convert these moles in to something else? Is the solid, As, a part of the calculation?

[Kim Tran 1J]

Yes, you would use the QC equation.

Since the problem only gives you moles and the equilibrium constant equation uses concentration (i.e. molarity which is mol/L), you would need to divide the given moles by 3.00 L in order to be able to calculate the QC.

And you would not include the solid as a part o your QC equation. When calculating the equilibrium constant, you do not include solids and liquids.

Your answer should be 2.01 x 10^-3

[Margaret Akey]

Don't forget to balance your chemical equation!

[Selina Bellin 2B]

yes, divide mol by L to get molarity/concentration, no solids or liquids in calculating this