LESSON PLAN

I. Identity

A. School Identity : Senior high school

B. Subject : Chemistry

C. Class/semester : XI/2

D. Topic : Chemical Equilibrium

E. Time Allocation : 30 minutes

II. Main Competence

1. Comprehending and applying religion that they believed.

2. Comprehending and applying honest, discipline, responsible, care (mutual

cooperation, tolerant, peaceful), well mannered, responsive and proactive behavior

and showing behavior as part of solution and become reflection of nation in world

association.

3. Understanding, applying, analyzing factual, conceptual, procedural and

metacognitive knowledge based on their curiosity about science, technology, art,

and culture with humanity, nationality, and civilization concerned with cause of a

phenomena and incident, and applying procedural knowledge in specific subject

based on their talent and interest to solving problem.

4. Processing, thinking logically, and performing concrete domain and abstract

domain concerned with developing what they learn at school individually, and

able to using scientific method.

III. Basic Competence

2.1 Showing scientific behavior (curiosity, discipline, honest, objective, open-

minded, able to distinguish fact and opinion, tough, careful, responsible, critical,

creative, innovative, democratic, communicative) in designing, executing

experiments and discussing that applied in daily life.

III.8. Analyzing factors that influence chemical equilibrium shifting that applied in

industry.

IV.8.Designing, conducting, concluding, and presenting experiment results of factor

that affecting the equilibrium.

VI. Indicators and Learning Goals

A. Indicator

Behavior

2.1.1 Showing their curiosity about effect of concentration to chemical

equilibrium.

2.1.2 Showing discipline behavior in learning.

2.1.3 Showing critical behavior in receiving statements.

Knowledge

3.8.1. Explaining effect of concentration to chemical equilibrium.

3.8.2. Predicting direction of equilibrium shifting based on change of

concentration.

Skills

4.8.1. Comunicating the demonstration result about effect of concentration to

chemical equilibrium.

B. Learning Objective

1. Students are able to explain the effect of concentration to chemical equilibrium

by observing a demonstration with discipline, curious and critical behavior and

communicate the demonstration result through written report.

2. Students are able to predict direction of chemical equilibrium shifting that

caused by concentration change with discipline, curious and critical behavior

through discussion.

VII. Topic

A. Prerequisite topic : Equilibrium state, equilibrium constant, reaction

quotien.

Equilibrium State

Equilibrium state exists when two opposing reactions occur simultaneously at

the same rate. Chemical equilibria are dynamic equilibria; that is, individual

molecules are continually reacting, even though the overall composition of the

reaction mixture does not change. In a system at equilibrium aA + bB ⇌ cC +

dD, the equilibrium is said to lie toward the right if more C and D are present

than A and B, and to lie toward the left if more A and B are present.

Equilibrium Constant

The equilibrium constant Kc, is defined as the product of the equilibrium

concentrations (moles per liter) of the products, each raised to the power that

corresponds to its coefficient in the balanced equation, divided by the product

of the equilibrium concentrations of reactants, each raised to the power that

corresponds to its coefficient in the balanced equation.

Reaction Quotien

The reaction quotient has the same form as the equilibrium constant, but it

involves specific values that are not necessarily equilibrium concentrations. If

they are equilibrium concentrations, then Q = Kc. The concept of the reaction

quotient is very useful. We can compare the magnitude of Q with that of Kc

for a reaction under given conditions to decide whether the forward or the

reverse reaction must occur to a greater extent to establish equilibrium.

B. Main topic : Chemical Equilibrium

C. Subtopic : Effect of concentration to chemical equilibrium

VIII. Learning Material

Many chemical reaction go to completion. The product cannot be converted

back to the reactants by a single reaction. The reaction is irreversible. Some

reaction can be reversed :

- When blue, hydrated copper(II) sulfate is heated, it decomposes into

white, anhydrous copper(II) sulfate and water :

CuSO4.5H2O(s) CuSO4(s) + 5H2O(l)

- When water is added into anhydrous copper(II) sulfate the reaction

reverses and blue copper sulfate is formed :

CuSO4(s) + 5H2O(l) CuSO4.5H2O(s)

- We can show these two reaction in one equation :

CuSO4.5H2O(s) ⇄ CuSO4(s) + 5H2O(l)

When the forward and backward reaction are happening at the same time, the

system is in equilibrium state. The product are being converted to reactants at the

same time as the reactants are being converted to products. So, equilibrium

reacion do not go to completion.

If a change of conditions (stress) is applied to a system at equilibrium, the

system shifts in the direction that reduces the stress to move toward a new state of

equilibrium. One of the stress is the change in concentration of components that

involve in the equilibrium system.

The example of equilibrium system is :

Co(H2O)62+ + 4Cl- ⇌ CoCl4

2- + 6H2O (l)

When CoCl2 is dissolved, it produce the pink solution, which is Co(H2O)62+

ion. When HCl is added into the solution, it turns into blue solution. This indicate

that the concentration of CoCl42- complex ion increase because equilibrium shift

to CoCl42- formation. But, when water is added, the solution turn back into pink

because equilibrium shift to Co(H2O)62+ formation.

Another example is the equilibrium system of K2Cr2O7 and K2CrO4 as this

equation :

2CrO42- (aq)+ 2H+(aq)⇌ Cr2O7

2- (aq) + H2O (l)

K=¿¿

When K2CrO4 is dissolve in the water, that equilibrium system will occur, that

means Cr2O72- ions also can be found in the solution. The solution of K2CrO4 is

yellow, and the solution of K2Cr2O7 is orange. When K2CrO4 is added by acid, it

turns into orange. This indicate that the concentration of Cr2O72- ion is increased

and conversely, the concentration of CrO42- is decreased because equilibrium has

shifted into Cr2O72- formation. When the solution is added by base, it turns

yellow. This indicate that the concentration of Cr2O72- ion is decreased and

conversely, the concentration of CrO42- is increased because equilibrium has

shifted into CrO42- formation.

Addition of acid will increase the concentration of H+ ion, so the ratio of

reactant and product concentration is larger that the ratio in equilibrium state (Q

is smaller than K). It makes more product formation until the equilibrium state is

reached back, and the equilibrium is shifted into product formation.

Addition of base into orange solution will decrease the concentration of H+

because it will react with OH- to form H2O, so the ratio of reactant and product

concentration is smaller than the ratio in equilibrium state (Q is bigger than K). It

cause reactant is formed again until the equilibrium is reached back.

IX. Learning Strategies

A. Learning Model : Constructivistic

B. Learning Approach : Guided Inquiry

C. Learning Method : Demonstration and discussion

X. Media and Learning Resources

A. Media : Student’s worksheet about effect of concentration to

chemical equilibrium; powerpoint slide, video; experiment tools and materials.

Tools :

- Test tube 1 pc

- Dropped pipette 3 pcs

- Test tube rack 1 pc

Materials :

- K2CrO4 0,1 M solution

- HCl 1 M solution

- NaOH 1 M solution

B. Learning Resources :

Sudarmo, Unggul. 2013. Kimia untuk SMA/MA Kelas X. Jakarta:Erlangga.

Sunarya, Yayan. 2009. Mudah dan Aktif Belajar Kimia 1. Jakarta : Pusat

Perbukuan Depdiknas.

XI. Learning Activity

Step of

ActivitiesActivities Duration

Attitude

Opening Teacher says greeting to students

Teacher and students pray together

Teacher checks student’s presence

Aperception and Motivation :

o Student watch a video of decomposition of

3 minutes Discipline

CuSO4.5H2O and the reverse reaction.

Teacher : In our last meeting, we have learned about

reversible reaction. The decomposition of

CuSO4.5H2O is one of reversible reaction.

Can you write the equation?

o Student write the chemical equation of CuSO4.5H2O

decomposition.

Teacher : How if the rate forward equal with rate

reverse reaction?

Student : The system is in equilibrium state.

Teacher : Good. How is the composition ratio of

product and reactant when attaining

equilibrium state?

Students : It always constant, Ma’am.

Teacher : If the reactant’s amount is different before

equilibrium state is reached, how is the

composition ratio of product and reactant

when attaining equilibrium state?

Students : The ratio will always be the same.

Teacher : Great. So, from what constant we know

ratio of reagent and products of an

equilibrium state?

Students : Equilibrium constant.

Teacher : What is the difference between equilibrium

constant and reaction quotient ?

Student : The concentration of each substance in the

system doesn’t necessarily equilibrium

concentration.

Teacher : Yes. Both of that constant will help us to

analyze what can system of reaction do to

keep in equilibrium. And today, we will

learn about that.

Main Inquiry syntax : Observation 3 minutes Critical

Activity Students are facilitated to observe phenomenon about the

reversible reaction of Co(H2O)62+ + 4Cl- ⇌ CoCl4

2- +

6H2O (l). The addition of Cl- ion into Co(H2O)62+ (pink)

solution will make the solution become blue (the color of

CoCl42-).

Students formulate problem related to the phenomenon.

Expected question :

- Why the change of concentration affect the

equilibrium?

- What is the effect of concentration to chemical

equilibrium?

Inquiry syntax : Manipulation

Students propose an experiment procedure to prove they

hypothesis

3 minutes Curiosity

Inquiry syntax : Generalization

To answer the problem, students pay attention into

teacher’s demonstration about equilibrium shifting of

K2CrO4 and K2Cr2O7 equilibrium system that caused by

change of concentration.

Teacher : “To answer your question, I will show a

demonstration, so pay attention to this. We

will see how the change of concentration

affecting equilibrium system.”

Students write the important things during demonstration

in the worksheet.

Teacher: “These are the tools and materials that will be

used. Look carefully and write some important

things on your worksheet.”

7 minutes Critical

Inquiry syntax : Verification

Students analyze and generalize observation data by filling

the questions in worksheet and guided by teacher.

8 minutes Critical

Inquiry syntax : Application

One of the students presents discussion result.

1 minute Critical

Closing Teacher and students make a conclusion about effect of

concentration to chemical equilibrium that they’ve learned.

If a change of conditions (stress) is applied to a system at

equilibrium, the system shifts in the direction that

reduces the stress to move toward a new state of

equilibrium.

When the reaction is in the equilibrium state, if the

concentration increases (the compound is added into

system), the system reacts to consume some of it. If the

concentration decreases (the compound is removed from

the system), the system reacts to produce some of it.

Student explain the relationship between the effect of

concentration to chemical equilibrium with daily life.

Students pray together

Teacher closes the learning with greeting

5 minutes Critical

XII. Evaluation

A. Assignment : Written experiment report

B. Form of evaluation : Written test, attitude assessment, skills assessment

C. Tools of evaluation : essay, observation form of attitude, observation form

of skills

XIII. Appendix

A. Student’s worksheet

B. Answer of student’s worksheet

C. Observation form of attitude

D. Knowledge Assessment

E. Observation form of skills

F. Powerpoint slides