Lesson Notes By Weeks and Term - Senior Secondary 2

TERM׃ 1^ST TERM

WEEK SIX

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:        

Subject: Chemistry

Topic: CHEMICAL REACTION 3

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Define chemical equilibrium.
2. Discuss the equilibrium constant.
3. State Le Chatelier’s principle and identify the factors that affects it. INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION	TEACHER’S ACTIVITY	STUDENT’S ACTIVITY
STEP 1 INTRODUCTION	The teacher explains chemical equilibrium to the students.	Students pay attention
STEP 2 EXPLANATION	He discusses the equilibrium constant.	Students pay attention and participates
STEP 3 EXPLANATION	Teacher explains the  Le Chatelier’s principle and discuss the factors that affects it.	Students pay attention and participates
STEP 4 NOTE TAKING	The teacher writes a summarized note on the board	The students copy the note in their books

 

NOTE

CHEMICAL REACTION 3

Chemical Equilibrium.

Chemical equilibrium is a state in a chemical reaction where the concentrations of reactants and products remain constant over time. This dynamic balance is achieved when the forward and reverse reactions occur at the same rate, resulting in no net change in the overall composition of the system.

Equilibrium Constant (K)

For a general reaction aA + bB     cC + dD, the equilibrium constant (K) is given by the ratio of the product concentrations to the reactant concentrations, each raised to the power of their respective coefficients in the balanced chemical equation:

 K = [C]^c[D]^d/[A]^a [B]^c

 

- If ( K > 1), the equilibrium favors the products.

- If ( K < 1), the equilibrium favors the reactants.

- If ( K = 1), the concentrations of products and reactants are roughly equal.

Law of Mass Action

The equilibrium constant expression is derived from the Law of Mass Action, which states that the rate of a chemical reaction is directly proportional to the product of the masses (concentrations) of the reacting substances, each raised to the power of their coefficients in the balanced chemical equation.

[ aA + bB   cC + dD ]

 

Rate = k[A]^a[B]^b

Le Chatelier's Principle

Le Chatelier's Principle helps predict how a system at equilibrium responds to changes in temperature, pressure, or concentration. If an external change is applied, the system will adjust itself to partially counteract that change.

- Concentration Changes: If the concentration of a reactant or product is changed, the system adjusts by shifting the equilibrium position to oppose the change.

- Temperature Changes: If the temperature is increased, the equilibrium will shift in the endothermic or exothermic direction, depending on the reaction.

- Pressure Changes: For reactions involving gases, changes in pressure can be offset by shifts in the equilibrium position.

EVALUATION: - Discuss chemical equilibrium

                            - Give an equation for equilibrium constant k

                            - State Le chatelier’s principle.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively