Equilibrium shift means change in concentrations of products/reactants. It can happen without change of Keq, for example when you keep the temperature constant, but change the pressure.
Thank you for clarifying. I think my real confusion is this: since Keq = [products]/[reactants], how can the equilibrium ever shift without changing Keq? You can't change the numerator or the denominator without changing the ratio, right?
Equilibrium shift means change in concentrations of products/reactants
Just to be 100% clear: equilibrium shift is not just a change in concentrations of products/reactants
from what they were before you stressed the system, but a change in what the concentrations of products/reactants
will be at equilibrium. In other words, equilibrium shift means that there is a new equilibrium point, characterized by different relative concentrations than there were at the old equilibrium point. Right?
Thanks for your patience, I'm self-teaching on this stuff and don't have an instructor.