How was the earth formed ?
The earth was formed billion years ago by expansion of the solar nebula. Solar nebula was cloud of gas and dust.
(a) What happens when carbon burns in air? Write the chemical equation of the reaction which takes place. (b) Why are coal and petroleum called fossil fuels? (c) Explain how coal was formed in the earth. (d) Describe how petroleum was formed in the earth. (e) Name a fossil fuel other than coal and petroleum.