Lesson Notes By Weeks and Term - Senior Secondary 2

Water I

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TERM: 2ND TERM

WEEK: ONE

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:        

Subject: Chemistry

Topic:-        WATER I

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

  1. Define the concept, Water
  2. Explain solubility and some basic concepts associated with solubility.
  3. identify factors that influence solubility
  4. Identify the uses of solubility curve.

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 introduces the concept, water and how it is formed.

Students pay attention

STEP 2

EXPLANATION

He explains solubility. He lists and explains the basic concepts of solubility.

 

Students pay attention and participates

STEP 3

DEMONSTRATION

He discusses the solubility curve.

Students pay attention and participate

STEP 4

NOTE TAKING

The teacher writes a summarized note on the board

The students copy the note in their books

 

NOTE

WATER

Water, with the chemical formula H₂O, is a vital compound in chemistry. It consists of two hydrogen atoms bonded to one oxygen atom. Its unique properties, such as high polarity and ability to form hydrogen bonds, make it essential for life and various chemical processes.

The structure of water is a bent or V-shaped molecule. It consists of two hydrogen (H) atoms bonded to one oxygen (O) atom. The oxygen atom is at the center, forming an angle of approximately 104.5 degrees between the two hydrogen atoms. This bent structure is due to the repulsion between the lone pairs of electrons on the oxygen atom.

Solubility

Solubility refers to the ability of a substance, known as the solute, to dissolve in another substance called the solvent, forming a homogeneous mixture known as a solution. This process occurs at the molecular level, where solvent molecules surround and interact with solute particles, overcoming attractive forces between solute molecules.

When a substance reaches its maximum solubility in a particular solvent under specific conditions, it is said to be saturated. If more solute is added and doesn't dissolve, it forms a separate phase. Conversely, a solution that can dissolve more solute is unsaturated.

Basic concepts of solubility

- Solute: The solute is the substance that is being dissolved in a solution. It is typically present in smaller amounts than the solvent. For example, in saltwater, salt is the solute.

- Solvent: The solvent is the substance in which the solute dissolves. It is the larger component of the solution. In the case of saltwater, water is the solvent.

- Solution: A solution is a homogeneous mixture composed of a solute dissolved in a solvent. The components are evenly distributed at the molecular level. The resulting mixture, like salt dissolved in water, is an example of a solution.

 Solubility is influenced by several factors:

  1. Temperature: In many cases, the solubility of a substance increases with temperature. This is true for many solid solutes in liquid solvents.
  2. Pressure: Pressure typically has a significant effect on the solubility of gases in liquids. For example, the solubility of gases in water usually increases with higher pressure.
  3. Nature of Solvent and Solute: The chemical nature of the solute and solvent plays a crucial role. "Like dissolves like" is a general rule, meaning polar solutes tend to dissolve in polar solvents, and non-polar solutes in non-polar solvents.
  4. Concentration: The concentration of solute in the solution can impact further dissolution. As the concentration approaches saturation, it becomes more difficult for additional solute to dissolve.
  5. Particle Size: Finely divided solute particles often dissolve more readily than larger particles due to increased surface area.

Uses of solubility curve

Solubility curves, which graphically represent how the solubility of a substance changes with temperature, have several practical uses:

  1. Chemical Process Design: Engineers use solubility curves to design processes involving the dissolution of substances. This is crucial in industries such as pharmaceuticals and chemicals.
  2. Quality Control: In manufacturing, solubility curves can be used to monitor and control the concentration of solutions. Deviations from expected solubility can indicate issues in the production process.
  3. Extraction Processes: In fields like food and beverage production, solubility curves are utilized to optimize extraction processes, ensuring maximum yield and quality.
  4. Pharmaceuticals: Solubility information is vital in drug formulation. It helps determine the best solvents and conditions for drug delivery systems, impacting drug absorption and effectiveness.
  5. Environmental Science: Understanding solubility is crucial in environmental studies. It helps predict the fate and transport of substances in natural systems, such as pollutants in water.
  6. Education and Research: Solubility curves are used in educational settings to teach students about the principles of solubility and how it varies with temperature.

EVALUATION: - What is water?

                          - How is water formed?

                          - Define solubility

                          - Enumerate the factors that affect solubility.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively