Equilibrium Constants and Reaction Quotients

The video tutorial explains the concept of the equilibrium constant, symbolized by 'K', which indicates the relative concentrations of reactants and products at equilibrium. It covers how to write equilibrium constant expressions for reactions, including those involving gases where partial pressures are used. The tutorial distinguishes between homogeneous and heterogeneous equilibria, emphasizing the exclusion of pure solids and liquids from expressions. It also introduces the reaction quotient 'Q', which helps determine if a reaction is at equilibrium by comparing it to 'K'.

What does the equilibrium constant K indicate in a chemical reaction?

• The pressure of the system

• The temperature at which the reaction occurs

• The relative concentrations of reactants and products at equilibrium

• The speed of the reaction

In an equilibrium constant expression, what do the coefficients in the balanced equation represent?

• The number of moles of each substance

• The power to which each concentration is raised

• The temperature of the reaction

• The initial concentrations of reactants

When writing an equilibrium constant expression for gases, what is often used instead of concentrations?

• Temperature

• Molarity

• Partial pressures

• Volume

What is the difference between Kc and Kp in equilibrium expressions?

• Kc is for homogeneous equilibria, Kp is for heterogeneous equilibria

• Kc is for reactants, Kp is for products

• Kc is for solids, Kp is for liquids

• Kc is for concentrations, Kp is for partial pressures

In a heterogeneous equilibrium, why are pure solids and liquids left out of the equilibrium constant expression?

• Their concentrations remain constant

• They have no effect on the reaction rate

• They do not react

• They are not part of the balanced equation

What is a homogeneous equilibrium?

• A reaction where substances are in different phases

• A reaction where all substances are in the same phase

• A reaction that occurs at constant temperature

• A reaction that involves only gases

What does the reaction quotient Q indicate?

• The relative concentrations of reactants and products at any moment in time

• The pressure of the system

• The speed of the reaction

• The temperature of the reaction

How can you determine if a reaction is at equilibrium using Q and K?

• If Q = K, the reaction is at equilibrium

• If Q < K, the reaction is at equilibrium

• If Q ≠ K, the reaction is at equilibrium

• If Q > K, the reaction is at equilibrium

What happens if Q is greater than K in a reaction?

• The reaction shifts to the right

• The reaction shifts to the left

• The reaction is at equilibrium

• The reaction stops

What is the significance of the coefficients in a balanced chemical equation when writing a Q expression?

• They determine the initial concentrations

• They are used as exponents for concentrations

• They indicate the reaction rate

• They are not used in Q expressions