STD VIII – CARBON AND ITS COMPOUNDS (Online)

Introduction:

In this theme children will learn the importance of carbon and some of its compounds.

It is a constituent of all plants and animals. In fact, a large number of compounds are

made up of carbon. It is a very versatile element.

Products such as paper, wooden furniture, soaps, food items are made up of carbon as

one of their elements and used extensively in daily life activities. The fuel that is used

in cars and trucks is also made of carbon.

Defining allotropes and explaining it with different examples, -diamond, graphite, coal, etc.

Emphasising on different physical

properties but same chemical

properties of allotropes.

Explaining that the properties such as electric and thermal conductivity of the two allotropes are different.

Emphasising that the difference in physical properties is due to their different structures. Showing the models of structures and discussing the differences.

Making models using clay dough /other molecular models.

Discussing the classification of crystalline and amorphous nature of carbon.

Defining Allotropes on the basis of their Crystalline and amorphous nature.

Making a list of the uses of diamond, graphite, coke, coal, soot from the literature and internet.

Demonstrating the preparation of CO2 from marble/ Na2CO3 and dil. HCl and showing its collection by upward displacement of air.

Showing physical properties of CO2 with its sample along with its fire extinguishing properties.

CO2 shows many important chemical reactions such as:

It is reacting with basic oxides such as Na2O, MgO to form metal carbonates.

Action on lime water: – showing that it turns lime water milky and on passing excess CO2, the milkiness disappears.

Explaining Fuel, if not burnt in a good supply of oxygen may lead to the formation of CO. (traditional cooking methods in villages using cow dung or wood).

Using it in industries as a reducing agent- in metallurgy of iron.

Explaining why we should not stand behind a running engine of a vehicle.

Discussing Government’s efforts to spread the use of LPG even to remote areas of the country.

Allotropes of carbon

Uses of graphite

As lubricant

As electrodes in electric furnaces

To make crucibles for melting metals and carbon brushes for electric motors

Pencil leads are made by mixing graphite with clay

As moderator in nuclear reactors

Uses of diamonds

As a gem in jewels

Cutting and drilling rocks, glass or other diamonds

Tips of drills in boring machines and needles in microsurgery and in LP record players

Radiation proof windows in space satellites