Matter Around Us

Objectives

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At the end of the lesson you will be able to - Define matter and develop an understanding of the particulate nature of matter - Sort the objects on the basis of certain properties - Differentiate between solids, liquids and gases based on the arrangement of their particles. - Differentiate between pure substances and mixtures - Identify the need for separation of mixtures - Suggest suitable methods for separating given samples of mixture - Acquire an awareness on food adulteration and its harmful effects

Summary

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- Matter is anything that has mass and occupies space. - All matter is made up of extremely small particles. - Matter is classified into solids, liquids and gases on the basis of two important factors . a. The way the particles are arranged b. The way the particles attract each other. - Difference between the properties of solids, liquids and gases is due to the difference in the arrangement of the particles and the nature of the attractive forces between them. - A pure substance can be an element or a compound and is made up of only one kind of particles. - A mixture is an impure substance containing two or more components physically mixed in any proportion. - Separation of mixtures is done 1) to remove harmful components 2) to obtain the useful component 3) to obtain a substance in a highly pure form - Separation method to be adopted depends on the properties of the components. - Handpicking – For smaller quantities containing particles reasonably large in size to be recognised can be picked by hand - Winnowing – Adopted to separate lighter solids from heavier ones - Magnetic separation – Used to separate magnetic substance from non-magnetic substance - Sedimentation – Settling down of suspended, insoluble and heavy solid particles (used to separate solid – liquid mixtures) - Decantation- Process of pouring out the clear supernatant liquid without disturbing the sediment - Filtration –Process of separating insoluble solid particles (residue) from a liquid (filtrate) by using a filter paper. - Adulteration – make impure by the addition of a foreign or inferior substance.