The pH Scale Cut & Stick Worksheet | KS3 Chemistry | Beyond - Free Printable

The image shows a pH Scale Activity Sheet with two parts: the original worksheet and its answer key. The task is to match common substances to their corresponding pH values on the pH scale, which ranges from 1 (strongly acidic) to 14 (strongly alkaline), with 7 being neutral.

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🔬 Understanding the pH Scale:

- pH < 7: Acidic
- pH = 7: Neutral
- pH > 7: Alkaline (basic)

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📋 Left Side – Substances to Match:

1. Milk
2. Acid rain
3. Tap water
4. Sodium Hydroxide
5. Vinegar
6. Hydrochloric Acid
7. Oven cleaner

(Note: "Milk" appears twice in the list — likely a typo or duplication.)

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✔ Right Side – Answer Key:

Here’s how each substance is matched:

| Substance | pH Value | Explanation |
|---------------------|----------|-----------|
| Milk | 6 | Slightly acidic due to lactic acid. |
| Acid rain | 4 | Rainwater with dissolved pollutants like sulfur dioxide and nitrogen oxides, making it more acidic than normal rain (which is around 5.6). |
| Tap water | 7 | Typically neutral, though can vary slightly depending on location. |
| Sodium Hydroxide| 14 | A strong base (alkali), commonly used in drain cleaners. |
| Vinegar | 3 | Contains acetic acid; moderately acidic. |
| Hydrochloric Acid| 1 | A strong acid, highly corrosive. |
| Oven cleaner | 13 | Contains strong bases like sodium hydroxide; very alkaline. |

> Note: In the answer key, "Oven cleaner" is connected to 13, and "Sodium Hydroxide" to 14.

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🔍 Step-by-step Matching Logic:

1. Hydrochloric Acid → Strong acid → pH 1
2. Vinegar → Weak acid → pH 3
3. Acid rain → Slightly more acidic than normal rain → pH 4
4. Milk → Slightly acidic → pH 6
5. Tap water → Neutral → pH 7
6. Oven cleaner → Strong alkali → pH 13
7. Sodium Hydroxide → Strongest base listed → pH 14

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🎯 Final Answer Summary:

| Substance | pH Value |
|-----------------------|----------|
| Milk | 6 |
| Acid rain | 4 |
| Tap water | 7 |
| Sodium Hydroxide | 14 |
| Vinegar | 3 |
| Hydrochloric Acid | 1 |
| Oven cleaner | 13 |

✔ This matches the answer key provided in the image.

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💡 Educational Insight:

This activity helps students understand:
- How everyday substances vary in acidity/alkalinity.
- The practical use of the pH scale.
- That not all acids or bases are equally strong (e.g., vinegar vs. hydrochloric acid).

Let me know if you'd like a printable version or a quiz based on this!