Year 7 Acids and Alkalis Worksheet - Beginner

Year 7 Acids and Alkalis worksheet for Year 7 (Key Stage 3 / Year 7-9 (Ages 11-14)). Beginner level science practice, aligned to the UK National Curriculum. Print-ready with answer key included.

Science•Key Stage 3 / Year 7-9 (Ages 11-14)•Acids and Alkalisbeginner

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Acids and Alkalis: pH, Indicators and Safety

Year 7 • Ages 11–12 • Beginner

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Instructions: Work through the activities in order. Use the pH scale and the data provided to help you, and show your thinking in the answer boxes. Remember: never taste or touch laboratory chemicals; follow your teacher’s instructions and the safety guidance in each question.

Reading the pH Scale

Use the pH scale facts below to classify each substance. A pH below 7 is acidic, pH 7 is neutral, and pH above 7 is alkaline. Write acidic, neutral or alkaline in each box.

pH scale: 0–6 = acidic; 7 = neutral; 8–14 = alkaline.

1. Lemon juice has pH 2.

2. Pure water has pH 7.

3. Soap solution has pH 10.

4. Vinegar has pH 3.

5. Baking soda solution has pH 8.

Indicators and Colour Changes

An indicator changes colour depending on whether a solution is acidic, neutral or alkaline. Use the results table to answer the questions. The universal indicator colours shown here are simplified for beginner practice.

Solution	Universal indicator colour	pH
Lemon juice	red	2
Vinegar	orange	3
Pure water	green	7
Baking soda solution	blue-green	8
Soap solution	purple	10

1. Which solution is neutral?

2. Which solution in the table is the most alkaline?

3. What colour did the indicator turn in vinegar?

4. A solution turns universal indicator red. Is it acidic, neutral or alkaline?

Strong and Weak Acids

For this beginner activity, use the pH values to compare the acidity of the examples. A lower pH means a more acidic solution; it does not tell you how concentrated the solution is. Use the word bank to complete each sentence.

Word bank: more acidic, less acidic, pH 1, pH 5

1. Compared with a solution at pH 5, a solution at pH 1 is ___.

2. Which pH shows the more acidic solution: pH 1 or pH 5? Write the pH.

3. A dilute acid can still be called a weak acid in everyday classroom comparisons, but pH alone does not prove whether an acid is strong or weak. What additional information would help make a fair comparison: the acid’s identity and concentration, or its colour?

Neutralisation

Neutralisation happens when an acid reacts with an alkali, producing a salt and water. In these examples, use the names provided to identify the salt and the other product. Write each answer in the box.

Example: hydrochloric acid + sodium hydroxide → sodium chloride + water

1. Hydrochloric acid + potassium hydroxide → potassium chloride + ___.

2. Nitric acid + sodium hydroxide → sodium nitrate + ___.

3. In the example equation, name the salt formed.

4. What type of substance reacts with an acid to neutralise it in these examples: an alkali or another acid?

Acids and Alkalis in Everyday Life

Read each everyday example and identify whether it is usually acidic, neutral or alkaline. These are general examples; real products can vary, so never test household products unless your teacher has specifically instructed you to do so safely.

1. Lemon juice, which contains citric acid:

2. Pure water:

3. A typical soap solution:

4. Vinegar, which contains ethanoic acid:

5. A baking soda solution:

Working Safely with Chemicals

Choose the safest answer for each situation. Select one option per question. Follow your teacher’s instructions and the safety rules used in your classroom.

1. Before handling a laboratory solution, what should you do?

2. If a chemical splashes on your skin, what should you do first?

3. Which is good practice when using a hazardous chemical?

4. What should you do with chemicals after an experiment?

Answer Key

Activity 1: 1. acidic ; 2. neutral ; 3. alkaline ; 4. acidic ; 5. alkaline

Activity 2: 1. Pure water ; 2. Soap solution ; 3. Orange ; 4. Acidic

Activity 3: 1. more acidic ; 2. pH 1 ; 3. The acid’s identity and concentration

Activity 4: 1. water ; 2. water ; 3. Sodium chloride ; 4. An alkali

Activity 5: 1. acidic ; 2. neutral ; 3. alkaline ; 4. acidic ; 5. alkaline

Activity 6: 1. Read the label and follow instructions ; 2. Tell your teacher and rinse as instructed ; 3. Wear the protective equipment instructed by your teacher ; 4. Dispose of them as instructed