NCERT Class VIII Science Solutions: Chapter 4-Materials: Metals and Non-Metals Part 2

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Question 5:

Some properties are listed in the following Table. Distinguish between metals and nonmetals on the basis of these properties.

Distinguish between Metals and Nonmetals
Distinguish between metals and nonmetals

Properties

Metals

Non-metals

Appearance

Hardness

Malleability

Ductility

Heat Conduction

Conduction of Electricity.

Answer:

Distinguish between Metals and Nonmetals Answer
Distinguish between metals and nonmetals Answer

Properties

Metals

Non-metals

Appearance

Lustrous

Dull

Hardness

Hard

Soft

Malleability

Malleable

Not malleable

Ductility

Ductile

Not Ductile

Heat Conduction

Good Conductor

Bad Conductor

Conduction of Electricity.

Good Conductor

Bad Conductor

Question 6:

Give reasons for the following:

  1. Aluminium foils are used to wrap food items.

  2. Immersion rods for heating liquids are made up of metallic substances.

  3. Copper cannot displace zinc from its salt solution.

  4. Sodium and potassium are stored in kerosene.

Answer:

  1. Aluminium foils are used to wrap food items because aluminium is highly malleable. It can be beaten into thin sheets. Moreover, it does not react with food.

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Aluminium Foils Are Used to Wrap Food Items

  1. Metals are good conductors of heat and electricity. Therefore, immersion rods for heating liquids are made of metallic substances.

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Metallic Substances

  1. The reactivity of zinc is higher than copper. Only a metal of higher reactivity can displace a metal of lower reactivity from its salt solution. So, copper cannot displace zinc from zinc sulphate solution.

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Copper Cannot Displace Zinc from Its Salt Solution

  1. Sodium and potassium are highly reactive metals. They can catch fire even when they come in contact with air. So, they have to be kept in kerosene.

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Sodium and Potassium Are Stored in Kerosene

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