Year 10 Science · Unit 2 · Lesson 3
Foundation Worksheet
Learning Goals
Match each term to its definition
Draw a line connecting each indicator on the left to its correct colour change on the right. Or write the matching letter next to each indicator.
| Indicator | Your answer | Colour change |
|---|---|---|
| Litmus | A. Colourless in acid → pink/magenta in base | |
| Universal indicator | B. Yellow in acid/base → red/pink in strong base | |
| Phenolphthalein | C. Red in acid, blue in base | |
| Red cabbage juice | D. Gives a full colour range from red (pH 1) through orange, yellow, green, blue to purple (pH 14) | |
| Turmeric | E. Pink/red at low pH → purple at neutral → blue/green at high pH |
Order the steps
Number the steps from 1 to 6 to show the correct order for safely testing the pH of household substances in a laboratory. Step 1 = what you do first.
| Order | Step |
|---|---|
| Record the colour of the indicator and match it to the pH scale reference chart. | |
| Put on safety goggles and gloves before handling any substances. | |
| Add a few drops of the household substance to a test tube or well plate. | |
| Wash hands thoroughly and clean equipment when the experiment is complete. | |
| Collect all substances, indicator solution, test tubes, and safety equipment. | |
| Add 2–3 drops of indicator (e.g. universal indicator) to the substance in the test tube. |
1. A student tests cola with red cabbage juice indicator and gets a red-pink colour. A second substance (bleach) turns the indicator yellow-green. State the approximate pH of each substance and classify each as acidic, neutral, or basic.
2. Explain why it is important to dilute concentrated household substances (such as bleach) before testing them with indicators in a school laboratory. Give two reasons.
Wrap Up
In one sentence, what was the main idea of this lesson?