Reaction Equilibrium
$Q$ symbolizes the mass action expression for any system ( not necessarily at equilibrium )
$$\ce{aA + bB <=>cC + dD}$$
$$Q = \frac{Products}{Reactants} = \frac{[C]^c*[D]^d}{[A]^a*[B]^b}$$
if ( products > reactants ) {Q === LARGE}else if ( reactants > products ) {Q === SMALL}