Question

science 10
topic: acids, bases and salts

learning session day 2
learning objectives:

• describe the ph scale and its significance
• classify aqueous solutions as acidic, basic, or neutral using their ph values.
• interpret ph data from diagrams, demonstrations, or simulations.
• explain the importance of ph in everyday life and environmental applications.

activity 1: explore the ph!
directions
study the ph scale and answer the questions below.

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$$\begin{array}{|c|c|c|} \\hline \\text{ph value} & \\text{classification} & \\text{strength} \\\\ \\hline 1-3 & \\text{_______} & \\text{_______} \\\\ 4-6 & \\text{_______} & \\text{_______} \\\\ 7 & \\text{_______} & \\text{_______} \\\\ 8-10 & \\text{_______} & \\text{_______} \\\\ 11-14 & \\text{_______} & \\text{_______} \\\\ \\hline \\end{array}$$

guide questions

1. which numbers represent acidic solutions?
2. which number represents a neutral solution?
3. how does acidity change as the ph decreases?
4. how does basicity change as the ph increases?

Explanation:

🆕 New Concept Discovered: pH Scale Classification
How to group solutions by acidity, basicity, and strength.

Step 1: Understand the pH Scale

The pH scale ranges from 0 to 14 and measures how acidic or basic a solution is:

• pH < 7: Acidic (lower numbers mean stronger acids)
• pH = 7: Neutral (neither acidic nor basic)
• pH > 7: Basic/Alkaline (higher numbers mean stronger bases)

Step 2: Fill in the Table

We classify each range based on its position relative to 7:

• 1–3: Far below 7. This represents a Strong Acid.
• 4–6: Just below 7. This represents a Weak Acid.
• 7: Exactly 7. This is Neutral (no strength classification needed).
• 8–10: Just above 7. This represents a Weak Base.
• 11–14: Far above 7. This represents a Strong Base.

pH Value	Classification	Strength
4–6	Acidic	Weak
7	Neutral	N/A (Neutral)
8–10	Basic	Weak
11–14	Basic	Strong

Step 3: Answer the Guide Questions

1. Which numbers represent acidic solutions?

• Any pH value less than 7 (specifically 1 to 6 on this table).

1. Which number represents a neutral solution?

• Exactly 7.

1. How does acidity change as the pH decreases?

• As pH decreases, the concentration of hydrogen ions increases, meaning the solution becomes more acidic (stronger acid).

1. How does basicity change as the pH increases?

• As pH increases, the concentration of hydroxide ions increases, meaning the solution becomes more basic (stronger base).

Answer:

Activity 1 Table

pH Value	Classification	Strength
4–6	Acidic	Weak
7	Neutral	Neutral
8–10	Basic	Weak
11–14	Basic	Strong

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Guide Questions

1. Which numbers represent acidic solutions?

• pH values from 1 to 6 (or any value less than 7).

1. Which number represents a neutral solution?

• 7

1. How does acidity change as the pH decreases?

• Acidity increases (the solution becomes a stronger acid).

1. How does basicity change as the pH increases?

• Basicity increases (the solution becomes a stronger base).