Chemistry Lesson Note On Acids, Bases, and Salts – Definitions, Examples, and Properties

Topic: Acids, Bases, and Salts – Definitions, Examples, and Properties

Class: SS1

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Specific Objectives

By the end of the lesson, students should be able to:

1. Define acids, bases, and salts.
2. Give common examples of acids, bases, and salts.
3. State the physical and chemical properties of acids and bases.
4. Describe how salts are formed.

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Instructional Materials

• Litmus papers (red and blue)
• Common laboratory acids and bases (e.g. HCl, NaOH)
• Samples of salts (e.g. NaCl, CuSO₄)
• Beakers, test tubes, dropper bottles
• Chart showing uses of acids, bases, and salts

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Lesson Content

Step 1: Definitions

• Acid: A substance that releases hydrogen ions (H⁺) in aqueous solution.

  • Example: HCl (hydrochloric acid), H₂SO₄ (sulfuric acid), CH₃COOH (acetic acid)

• Base: A substance that releases hydroxide ions (OH⁻) in aqueous solution or accepts hydrogen ions.

  • Example: NaOH (sodium hydroxide), KOH (potassium hydroxide), NH₃ (ammonia)

• Salt: A compound formed when the hydrogen ion of an acid is replaced by a metal or ammonium ion.

  • Example: NaCl (sodium chloride), KNO₃ (potassium nitrate)

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Step 2: Examples of Acids, Bases, and Salts

Type	Examples	Sources/Uses
Acids	HCl, H₂SO₄, CH₃COOH	Cleaning agents, batteries, vinegar
Bases	NaOH, KOH, NH₃	Soap making, fertilizers
Salts	NaCl, CuSO₄, KNO₃	Table salt, medicine, explosives

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Step 3: Properties of Acids and Bases

Acids:

• Sour taste (do not taste in the lab!)
• Turn blue litmus paper red
• React with metals to produce hydrogen gas
• Neutralize bases to form salts and water

Bases:

• Bitter taste and slippery feel
• Turn red litmus paper blue
• React with acids to form salts and water
• Some bases are soluble in water (alkalis), e.g. NaOH

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Step 4: Formation of Salts

Salts can be formed through:

1. Neutralization reaction:

   \text{Acid + Base} \rightarrow \text{Salt + Water}

   \text{HCl + NaOH} \rightarrow \text{NaCl + H₂O}

2. Reaction of acid with a metal:

   \text{2HCl + Zn} \rightarrow \text{ZnCl₂ + H₂}

3. Reaction of acid with a metal carbonate:

   \text{H₂SO₄ + CaCO₃} \rightarrow \text{CaSO₄ + H₂O + CO₂}

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Evaluation

1. Define acids, bases, and salts.
2. Mention two examples of each: acids, bases, and salts.
3. State two physical properties each of acids and bases.
4. What is a neutralization reaction?
5. Write a balanced equation to show the formation of salt from an acid and base.

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Homework

1. List three acids commonly found in the home and their uses.
2. Write balanced chemical equations for the reactions between:
   a) HNO₃ and KOH
   b) HCl and Mg
   c) H₂SO₄ and Na₂CO₃
3. Explain how you can test a substance to know if it is an acid or a base.

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Conclusion

Acids, bases, and salts are important classes of chemical substances with wide-ranging uses in industry and daily life. Understanding their properties and reactions helps in recognizing their roles in chemical processes.