Final answer:
The equilibrium constant K is found by writing an expression from the balanced chemical equation and plugging in the concentrations of the reactants and products at equilibrium. K remains consistent if the plugged-in values satisfy the equilibrium expression. In reactions involving water, the concentrations of hydrogen ions and hydroxide ions are related by the ion product of water (Kw).
Step-by-step explanation:
To find the equilibrium constant K in chemical equations, you need to write the expression for K based on the balanced chemical equation. The equation will typically include brackets representing the concentrations of the reactants and products at equilibrium. The concentration, represented by the square brackets, means 'molarity' or moles per liter. According to the provided data, we see concentrations of various chemicals in the reaction. We use these concentrations to calculate K.
For example, if the equilibrium equation was H2O + CO → H2 + CO2, then the equilibrium expression would be K = [H2][CO2] / [H2O][CO]. You would plug in the given concentrations into this expression to calculate the value of K. If given values fit the expression so that K remains consistent, the calculations are confirmed.
Additionally, in reactions involving water such as Kw, the ion product of water, the relation between the hydrogen ion concentration [H+] and hydroxide concentration [OH−] is important. For example, Kw = [H+][OH−], which has a constant value of 1.0 × 10−14 at 25°C. Thus, if you know one concentration, you can calculate the other to maintain the constant value of Kw.