In a pure substance, all the constituent particles are the same in their chemical nature. But most of the matter we see and use is constituted by more than one kind of pure substances and are known as mixtures. For e.g. milk is actually a mixture of water, fat, proteins etc. Seawater, sugar, minerals, soil, nylon, cotton, oil, paper, air etc. are all mixtures. Mixtures may be homogeneous or heterogeneous.”
