8 posts • Page 1 of 1
We only use gases and aqueous solutions in K expressions. Solids don't have concentrations so they are not included and pure substances (liquids) will not react enough to make any effect so they are left out as well.
When writing the equilibrium constant expression we don't include solids and liquids because, as Dr. Lavelle said in class, the molar concentration of a pure substance doesn't change in a reaction and thus, does not need to be included.
The concentration of liquids (solutes) and solids are not included in the calculation of the equilibrium constant because of the inability to apply this characteristic to these phenomena and have it possess and plausible meaning. Solutes, in a reaction at equilibrium, have an insignificant change in concentration, so it is safe to approximate the true value of K and leave out the solute. Solids are excluded because solids do not have a concentration fundamentally.
Who is online
Users browsing this forum: No registered users and 1 guest