Class 8 Science Chapter 3 Materials: Metals and Non-metals Solutions | ASSEB Assam | English Medium

Class 8 Science Chapter 3 – Materials: Metals and Non-metals – All Textual Solutions | ASSEB Assam (English Medium)

Class 8 Science Chapter 3 – Materials: Metals and Non-metals Complete Textual Questions and Answers (ASSEB / SEBA Assam – English Medium)

Chapter 3 of the Class 8 Science curriculum, ‘Materials: Metals and Non-metals’, is a highly fundamental chemistry chapter for students. These complete textual question-answer solutions (Class 8 Science Chapter 3 Textual Solutions) have been meticulously prepared based on the latest guidelines of the new ASSEB (Assam State School Education Board) syllabus and the National Education Policy (NEP). This comprehensive compilation includes textbook-based Very Short Answers (VSA), Short Questions, Long Answers, chemical equations, explanations, and key definitions. Ospin Academy provides these solutions in a simple, accurate, and completely exam-oriented format.

The chapter ‘Materials: Metals and Non-metals’ provides an in-depth understanding of the physical properties of materials (such as malleability, ductility, sonority, and conductivity) and their distinct chemical properties (reactions with oxygen, water, acids, and bases, alongside displacement reactions). It is essential for students to thoroughly grasp these core concepts, reaction behaviors, and practical applications outlined in this lesson. Our textual solutions not only cover all the standard textbook exercises but also include important additional exam-oriented questions to ensure robust preparation.

What you will learn and get from these textual solutions:

• Clear explanations of physical properties distinguishing metals from non-metals, including exceptions like mercury and sodium.
• Accurate, point-wise answers for 1-mark objective questions (VSA) and 2-3 mark short textual questions.
• Standard and easy-to-understand explanations for 4-5 mark descriptive questions, give-reason type questions, and displacement reactions.
• Complete coverage of end-of-chapter exercises, fill-in-the-blanks, matching questions, and reaction descriptions.
• Extra important questions aligned with the new syllabus structure alongside standard MCQ solutions.

Exclusive features of Ospin Academy’s solutions:

• Fully textbook-based answers formulated strictly according to the latest ASSEB new syllabus guidelines.
• 100% accurate, high-quality notes written in simple English language for effortless memorization and understanding.
• Concise summaries and targeted answers specifically designed for quick revision before examinations.
• A curated selection of highly probable extra questions to give students a competitive edge.

Committed to the academic excellence of students, Ospin Academy offers these high-quality textual solutions. Start your preparation today to master the concepts of Science and achieve top scores in your upcoming examinations.

Class 8 Science

Chapter – 3                             Ospin Academy

Materials: Metals and Non-Metals

TEXTBOOK EXERCISES

Q. 1. Which of the following can be beaten into thin sheets?

(a) Zinc.

(b) Phosphorus.

(d) Oxygen.

(c) Sulphur.

Ans. (a) Zinc.

Q. 2. Which of the following statements is correct?

(a) All metals are ductile.

Ans. ×.

(b) All non-metals are ductile.

Ans. ×.

(c) Generally, metals are ductile.

Ans. ✓.

(d) Some non-metals are ductile.

Ans. ×.

Q. 3. Fill in the blanks:

(a) Phosphorus is very __________ non-metal.

Ans. Reactive.

(b) Metals are __________ conductor of heat and __________.

Ans. good, electricity .

(c) Iron _________ reactive than copper.

Ans. less.

(d) Metals react with acids to produce _________ gas.

Ans. hydrogen.

Q. 4. Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) Generally, non-metals react with acids.

Ans. F.

(b) Sodium is a very reactive metal.

Ans. T.

(c) Copper displaces zinc from zinc suphate solution.

Ans. F.

(d) Carbon can be drawn into wires.

Ans. F.

Q. 5. Some properties are listed in the following table. Distinguish between metals and nonmetals on the basis of their properties.

Properties	Metals	Non-metals
1. Appearance
2. Hardness
3. Malleability
4. Ductility
5. Heat Conduction
6. Conduction of Electricity

Ans.

Properties	Metals	Non-metals
1. Appearance	lustrous	non – lustrous
2. Hardness	hard except sodium and potassium	generally soft except diamond
3. Malleability	generally malleable	non-malleable
4. Ductility	generally ductile	non-ductile
5. Heat Conduction	good conductors	poor conductors
6. Conduction of Electicity	good conductors	poor conductors

Q. 6. Give reasons for the following:

(a) Aluminium foils are used to wrap food items.

Ans. Aluminium foils are used to wrap food items because aluminium can be beaten in sheets to form these thin wrapping sheets and it is soft and it does not react with food items.

(b) Immersion rods for heating liquids are made up of metallic substances.

Ans. Immersoin rods are made up of metallic substances because metals are good conductors of heat and electricity. They get hot very soon on passage of current and warm the water.

(c) Copper cannot displace zinc from its salt solution.

Ans. Copper cannot displace zinc from its salt solution because copper is less reactive than zinc. A less reactive metal cannot displace a more reactive metal from its solution.

(d) Sodium and potassium are stored in kerosene.

Ans. Sodium and Postassium are stored in kerosene because they are very reactive and quickly react in air.

Q. 7. Can you store acidic lemon pickles in an aluminium utensils? Explain.

Ans. No, we cannot store acidic lemon pickles in aluminium utensils because aluminium is metal. Metals readily react with acids to produce hydrogen gas. So, when the aluminium metal comes in contact with acidic lemon pickles, it would react to release hydrogen, which would spoil the food and render it unfit to consume.

Q. 8. In the following table some subs-tances are given in Column I. In Column II some uses are given. Match the items in Column I with those in Column II.

Column I	Column II
(i) Gold	(a) Thermometers
(ii) Iron	(b) Electric wire
(iii) Aluminium	(c) Wrapping food
(iv) Carbon	(d) Jewellery
(v) Copper	(e) Machinery
(vi) Mercury	(f) Fuel

Ans.

Column I	Column II
(i) Gold	(d) Jewellery
(ii) Iron	(e) Machinery
(iii) Aluminium	(c) Wrapping food
(iv) Carbon	(f) Fuel
(v) Copper	(b) Electric wire
(vi) Mercury	(a) Thermometers

Q. 9. What happens when:

(i) Dilute sulphuric acid is poured on a copper plate?

Ans. When sulphuric aicd is poured on copper plate the acid present in sulphuric acid reacts with copper to form copper sulphate and hydrogen. The copper plate gets eroded from place.

Sulphuric acid + Copper → Copper sulphate + Hydrogen

(ii) Iron nails are placed in copper sulphate solution? Write word equations of the reactions involved.

Ans. When iron nails are placed in copper sulphate solution, the iron being more reactive will replace copper in its salt solution.

(Ferrous sulphate) → Iron + Copper

sulphate → Iron Sulphate + Copper

The blue colour turns into green.

Q. 10. Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.

(a) How will she find the nature of the gas?

Ans. She will test it with litmus paper to check the acidic or basic nature of gas. If red litmus turns blue, it is basic in nature. If blue litmus turns red, it is acidic in nature.

(b) Write down equations of all the reactions taking place in this process.

Ans. Sulphur dioxide (SO₂) + Water (H₂O) → Sulphurous acid (H₂SO₂).

Q. 11. One day Reeta went to a Jeweller’s shop with her mother. Her mother gave old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back they found that there was a loss in its weight. Can you suggest a reason for the loss in weight?

Ans. When gold is washed in acidic solution, it being a metal reacts with acid and forms the hydrogen gas with some metallic oxide. This causes the loss of gold in form of gold oxides. This losses the weight of gold.