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

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.

India’s first smartcard-based Public Bicycle Sharing (PBS) initiative has launched in Mysuru, Karnataka on June 4, 2017. The cost of the project, partly funded by World Bank’s Global Environmental Facility, for the next six years is Rs 20.5 crore, covering the maintenance of the docking stations and bicycles. About 450 bicycles will be available for public use in the city. To rent a bicycle, the citizens of Mysuru or tourists need to register themselves either online or by visiting one of the six registration centres situated close to tourism centres and obtain a smart card after paying Rs. 350, including a refundable deposit of Rs. 250. Though the use of the bicycle is free for the first one hour, the users will have to pay a nominal fee of Rs. 5 for two hours, Rs. 10 for three hours and so on.

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.

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.