Chemical Equilibrium Grade 12 Notes with Questions and Answers pdf Download Chemical equilibrium is a fundamental concept in chemistry that is crucial for understanding how reactions proceed and reach a state of balance. In Grade 12 chemistry, students delve deeper into the intricacies of chemical equilibrium, exploring the factors that influence it and how it can be manipulated. In this blog post, we’ll provide a comprehensive overview of chemical equilibrium, along with Grade 12 notes, questions, and answers to help solidify your understanding.
What is Chemical Equilibrium?
Chemical equilibrium occurs in a reversible reaction when the forward and reverse reactions proceed at equal rates. At equilibrium, the concentrations of reactants and products remain constant over time, although the reactions continue to occur. This dynamic state is characterized by the equilibrium constant (K), which expresses the ratio of the concentrations of products to reactants at equilibrium.
Grade 12 Notes on Chemical Equilibrium:
- The Law of Mass Action: This law states that the rate of a chemical reaction is directly proportional to the product of the concentrations of the reactants, each raised to the power corresponding to its stoichiometric coefficient in the balanced chemical equation.
- Equilibrium Constant (K): For a general reaction:aA+bB⇌cC+dD
The equilibrium constant expression (K) is given by:
K=[C]câ‹…[D]d[A]aâ‹…[B]b
- Factors Affecting Equilibrium:
- Concentration Changes
- Pressure Changes (for gases)
- Temperature Changes
- Addition of Catalysts
- Le Chatelier’s Principle: This principle states that if a system at equilibrium is subjected to a change in concentration, pressure, or temperature, the system will shift its position to counteract the imposed change and restore equilibrium.
Questions and Answers:
- What is the difference between static and dynamic equilibrium?
- Static equilibrium refers to a system where there is no net change occurring, whereas dynamic equilibrium is a state of balance where reactions are still occurring, but the rates of the forward and reverse reactions are equal.
- How does an increase in pressure affect an equilibrium involving gases?
- According to Le Chatelier’s Principle, an increase in pressure will shift the equilibrium towards the side with fewer moles of gas to reduce the pressure.
- If the concentration of a reactant is increased, how will the equilibrium shift?
- The equilibrium will shift in the direction that consumes the added reactant to partially offset the increase in concentration, ultimately restoring equilibrium.
- What is the significance of the equilibrium constant (K) in a chemical reaction?
- The equilibrium constant indicates the extent to which a reaction proceeds at equilibrium. A larger value of K signifies that the equilibrium favors the formation of products, while a smaller value indicates a preference for the reactants.
- Why does adding a catalyst not affect the value of equilibrium constant (K)?
- A catalyst speeds up both the forward and reverse reactions equally, thereby reducing the time taken to reach equilibrium without affecting the concentrations of reactants and products at equilibrium.
Downloadable Notes on pdf
Watch: Chemistry | Chemical equilibrium | Le Chartelie’s Principle
Chemical Equilibrium Test for Grade 12
The test (question bank) below gives the Grade 12 learners extra practice problems for revisions. The test covers the following: Equilibrium Conceptual, Writing the Equilibrium Constant, Manipulations of K: Reversing or Multiplying, Solving for K given all equilibrium concentrations, solving for an equilibrium concentration given K and other equilibrium concentrations, Using Ice, and more.
Shifts in Equilibrium in Response to stress Table
Below is the table which shows how does a system at equilibrium adjust to the changes in temperature, Volume, Concentration, Catalyst, and Inert Gas:
