Pure Substances : Elements and Compounds
A pure substance is one which is made up of only one kind of particles. These particles may be atoms or molecules. So, we can also say that a pure substance is one which is made up of only one kind of atoms or molecules.For example, sulphur element is made up of only one kind of particles (called sulphur atoms),therefore, sulphur is a pure substance. Similarly, water is made up of only one kind of particles (called water molecules), therefore, water is a pure substance. All the elements and compounds are pure substances because they contain only one kind of particles. Thus, all the elements like hydrogen, oxygen, nitrogen,chlorine, bromine, iodine, carbon, sulphur, iron, copper, silver, gold, mercury and silicon, are pure substances. Similarly, all the compounds such as water (including ice and steam), carbon dioxide, sodium chloride, sugar, copper sulphate, alum (aluminium potassium sulphate), calcium oxide, sodium hydroxide,hydrochloric acid, sulphuric acid, nitric acid, potassium permanganate, camphor, naphthalene and sand (silicon dioxide), are pure substances. A pure substance is homogeneous throughout its mass. A pure substance cannot be separated into other kinds of matter by any physical process. A pure substance has a fixed composition as well as a fixed melting point and boiling point.
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Matter in Our Surroundings - Notes
2. 7. Metals are Solids at the Room Temperature
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4. 3. Non-Metals are Bad Conductors of Heat and Electricity.
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8. 7. Non-Metals may be Solid, Liquid or Gases at the Room Temperature.
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9. 11. Non-Metals Have Many Different Colours.
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15. 8. Metals Generally Have High Melting Points and Boiling Points.
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19. 8. Non-Metals Have Comparatively Low Melting Points and Boiling Points
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23. To Study the Properties of a Suspension
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24. Chemical Formula for daily use material
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25. Effect of Temperature and Pressure on Solubility
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26. 1. Non-Metals are Not Malleable. Non-Metals are Brittle.
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32. Pure Substances : Elements and Compounds
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33. 3. Metals are Good Conductors of Heat and Electricity.
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34. 4. Non-Metals are Not Lustrous (Not Shiny). They are Dull in Appearance.
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37. 1. Separation by a Suitable Solvent
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38. Solutions, Suspensions And Colloids
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46. Comparison Among the Properties of Metals and Non-Metals
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47. Differences Between Mixtures and Compounds
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50. Separation Of Mixture Of a Solid And a Liquids
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