Chemistry

Coal is a hard rock that can be burned as a solid fossil fuel. It is mostly carbon but also contains hydrogen, sulfur, oxygen, and nitrogen.

Hydrocarbons made of hydrogen and carbon and compounds that are derived from hydrocarbons are known as organic compounds.

The word aromatic is taken from the Greek word aroma which means scent or fragrance. The aromatic compounds are generally 5, 6 or 7 membered co-planer cyclic compounds. It has alternative double bonds that mean there is a carbon-carbon single bond and a then carbon-carbon double bond.

The monomer of protein is amino acid.

The molten mix of different substances that pour out from the volcanoes is called magma.

The solid substance obtained from mixing any molten metal or nonmetal with another molten metal and cooling the mixture is called alloy.

Nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus and it is accompanied by the release or absorption of energy depending on the masses of the nuclei involved.

In mathematical terms, the value of pH may be any number from negative to positive, in reality, the value is measured on a scale of 0 to 14.