Metals and Non-Metals is a chapter in DAV Class 8 Science book. This chapter discusses the properties of metals and non-metals and how they react with different substances. We have tried to share the best answers for DAV Class 8 Science Chapter 3 Questions.
DAV Class 8 Science Chapter 3 Solutions
Metals and Non Metals Question Answers
A. Fill in the Blanks
1. The property, due to which a metal piece can be hammered into thin sheets, is known as ___________.
2. Bronze is an alloy of ___________ and ___________.
3. Gold is mixed with ___________ and /or ___________ to make it hard.
4. ___________ is the only non-metal to have a natural lustre.
5. ___________ is a non-metal which catches fire in air.
6. The only metal, which exists in the liquid state at room temperatures, is ___________.
Ans:
- Malleability
- Copper and Tin
- Silver, Copper
- Iodine
- Phosphorus
- Mercury
B. Match the following:
Ans: (1) d, (2) c, (3) a, (4) b, (5) e
C. Tick the correct option
1. The two most abundant metals, found in the earth’s crust, are-
Answer: Aluminium (Al) Iron (Fe)
2. The metals, used in making the alloy ‘german silver’, are-
Answer: Copper, zinc and nickel
3. When a metal reacts with oxygen, the resulting oxide of the metal-
Answer: is a basic oxide
4. Out of the metals, gold, silver, copper and aluminium, the one, that is most ductile, is
Answer: Gold (Au)
5. Two of the metals, that cannot be stored either in air, or under water, are-
Answer: Potassium(K) and sodium (Na)
D. Answer the following questions in brief:
1. Name (i) one metal and (ii) one non-metal which normally exists in the liquid state.
Ans: (i) Mercury is a metal that exist in liquid state
(ii) Bromine is a non-metal that exists in liquid state
2. State the fraction of Gold present in an 18 K gold piece
Ans. If we have 24K gold then it will contain only18 K gold and the rest will be some other substance. So, the fraction of Gold is 18/24.
3. State the property of copper wires that makes them useful for electrical fittings.
Copper wires are ductile in nature which means that they can be converted into thin sheets. They are cheaper as compared to other alternatives for wiring. They are good conductors of electricity that’s why they are used in electrical fittings in the home.
4. Define an Alloy
Alloy is a mixture of a metal and a non metal or more than two metals. Some examples of alloy areL Bronze ( alloy of Copper snd Tin)
5. List any two uses of Non Metals
Chlorine is used for purification of water
Nitrogen is used as fertilizers
E. Answer the following questions
1. Write balanced chemical reactions for the following
Sodium reacts with oxygen
4Na + O2 –> 2Na2O
Aluminium reacts with dilute hydrochloric acid
2Al + 6HCl —> 2AlCl3 + 3H2
2. Why are Gold and Platinum suitable for making jewellery?
Gold and Platinum are suitable for making jewellery because
They are malleable and ductile in nature
They have lustre which is good for jewellery.
They comes under the least reactive metals so they maintain their shine for a longer period of time.
3. Sodium and Potassium is stored under Kerosene. Give reasons
Sodium and potassium are highly reactive in nature so they are kept immersed in Kerosene because if we bring them in open they will react instantly. They also react vigorously with water and catch fire.
4. Why is bronze preferred over coppper metal for making statues?
Bronze is preferred over Copper metal because Bronze is an alloy of Copper and Tin. It has higher strength and has better resistance to corrosion as compared to the Copper metal. The statues can be protected for a longer time.
So, these were the solutions to DAV Class 8 Science Chapter3, Metals and Non Metals Question Answers. If you have any query, feel free to ask through the comments section below. Stay tuned to CareerAdvice4u.
- DAV Class 7 Science Solutions With Explanations: All Chapters - February 6, 2022
- Pollution of Water Question Answers | DAV Class 8 Science - February 4, 2022
- Fabric from Fibre Solutions | DAV Class7 Science Chapter 14 - January 25, 2022
Leave a Reply