Exploring Acids, Bases & Salts: Grade 7 Science
Exploring Acids, Bases & Salts
Lesson duration is: 16 minItems in this lesson
Exploring Acids, Bases & Salts
What do you already know about acids, bases, and salts?
Learning Objective
At the end of the lesson you will be able to classify substances as acids, bases or salts; describe their properties; and answer questions based on the NCERT Grade 7 Science chapter.
Multiple Choice Questions
1. Which of the following is an acid? a) Soap b) Lemon juice c) Baking soda d) Sugar 2. Litmus paper turns red in: a) Base b) Neutral solution c) Acid d) Salt 3. Common salt is also called: a) Sodium carbonate b) Sodium chloride c) Potassium chloride d) Magnesium sulphate 4. Which substance turns blue litmus paper red? a) Vinegar b) Soda water c) Toothpaste d) Detergent 5. A base tastes: a) Sweet b) Bitter c) Salty d) Sour
Fill in the Blanks
1. Substances that taste sour contain ________. 2. Bases turn red litmus paper ________. 3. The chemical name of common salt is ________. 4. Acids are found in lemon and ________. 5. Neutralisation produces salt and ________.
Very Short Answer Questions
1. What is an indicator? 2. Give one example of a natural acid. 3. Name one base used at home. 4. What is formed when an acid reacts with a base? 5. Write the colour of litmus in a basic solution.
Short Answer Questions
1. Why do acids not show acidic behaviour in the absence of water? 2. How can you test if a substance is acidic or basic? 3. Name two uses of bases in daily life. 4. Why is neutralisation important? 5. What happens when you mix baking soda with lemon juice?
Long Answer Questions
1. Explain the process of neutralisation with an example. 2. Describe the properties and uses of acids, bases, and salts in daily life.
Case Study Question
During a science experiment, Riya added lemon juice (citric acid) to a beaker containing a solution of baking soda. She observed bubbling and the gas released turned lime water milky. (a) Which type of reaction took place? (b) Why did bubbles appear? (c) Name the gas released.
Answer Key
MCQs: 1-b, 2-c, 3-b, 4-a, 5-b. Fill in the blanks: 1. acid, 2. blue, 3. sodium chloride, 4. orange, 5. water. Very Short: 1. Substance that shows acids/bases, 2. Lemon, 3. Soap, 4. Salt and water, 5. Blue. Short: 1. Need water for H+ ions, 2. Use indicator, 3. Soap, antacid, 4. To correct acids/bases, 5. Carbon dioxide gas. Long: 1. Mixing acid & base to give salt + water (eg: HCl + NaOH), 2. Refer properties and uses discussed. Case study: (a) Neutralisation, (b) CO2 gas formed, (c) Carbon dioxide.
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.
