Question

Whcih of the following substances are elements water, salt , mercury, iron, marble, diamond, wood , nitrogen, air, graphite, dydrogen, oxygen, sugar, chlorine

Answer 1

compound- water,salt,marble,diamond,wood,air(mixture),sugar,graphite
element -mercury ,iron,nitrogen,dydrogen , oxygen

Answer 2

SUBSTANCES THAT ARE ELEMENTS:

            Compounds are the mixture of two or more elements to make a stable component. From the above given list, water is a compound made of hydrogen and oxygen.

            Salt it is a compound made up of sodium and chlorine similarly air, diamond, Graphite and sugar all are made out of more than one component hence come under compounds.

While oxygen, hydrogen, iron, nitrogen and mercury are not mixtures and are found in nature as it is hence they named as elements.