Questions

A pure substance can be defined as any single type of material that has not been contaminated by another substance. In chemistry, a pure substance has a definite composition. It can be a compound or an element. A pure substance is considered to be a material that consists of one type of "building block" of matter.

Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate).

Tin, sulfur, and diamond are examples of pure substances which are chemical elements. All elements are pure substances.

Water, sugar, salt and baking soda are pure substances which are chemical compounds. Chemical compounds also are pure substances

The Edwardian era (1901-1914) is the last period in British history to be named after the monarch who reigned over it. Although Edward VII reigned from 1901 to 1910 to be succeeded by George V, the Edwardian period is generally considered to have ended at the outbreak of the First World War in 1914.

In the periodic table, the atomic radius increases from top to bottom in the groups and it increases from right to left in the periods.

Francium is the atom with largest atomic radius. Helium is the atom with smallest radius.

Ethiopia is the new name of a country which is historically called as Abyssinia.

New name     -      Old name

Namibia        -      South West Africa

Zimbabwe     -      Southern Rhodesia

Thailand        -      Siam.

Grey Revolution is associated with Fertilizers.

• Cotton - Silver fiber Revolution

• Fruits - Golden Revolution

• Oil seeds - Yellow Revolution