L27 - Equilibrium

Impact of change on the equilibrium constant Effect of pressure, volume, temperature

What does a Kc value represent?

Concentrations, as indicated by the 'c' in Kc.

What is an ICE table?

A table used to organize initial concentrations, changes in concentration, and equilibrium concentrations of reactants and products.

If you start with only reactants, in which direction must a reaction shift to reach equilibrium?

The reaction must shift towards the products to reach equilibrium.

How is the equilibrium constant (Kc) expressed?

Represented by the product concentrations divided by the reactant concentrations at equilibrium.

To solve for x after creating an ICE table, what must you do?

Write your equilibrium concentrations in terms of a single unknown quantity x.

How do you solve for x when you can't take the square root of both sides of the equation?

Expanding the equation and moving all terms to one side to obtain a quadratic equation.

What is the quadratic formula?

x = (-b ± √(b^2 - 4ac)) / 2a

If the equilibrium constant is small, what does this indicate about the relative amounts of reactants and products at equilibrium?

The equilibrium constant is the product concentrations divided by the reactant concentrations. If K is small, you'll mainly have reactants.

When can you make a simplifying assumption to solve for x?

Assume that the change (x) is much smaller than the initial concentration.

How do you check if your simplifying assumption was valid?

Compare the calculated value of x to the initial concentrations to ensure it is small enough (e.g., less than 1%).

If you initially have both reactants and products, how do you determine which direction the reaction will shift to reach equilibrium?

Calculate the reaction quotient (Q) using initial concentrations and compare it to the equilibrium constant (K).

How does comparing Q to K tell you which way the reaction will shift?

If Q < K, the reaction will shift towards the products. If Q > K, the reaction will shift towards the reactants.