17. Compounds C omposed of different elements combined in a fixed ratio Hydrogen + Oxygen Water 2 Hydrogen + 1 Oxygen 1 Water
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19. Compounds Guess the elements present Sulfur dioxide Silver nitrate Iron(II) sulfate Nitrogen dioxide Magnesium chloride
20. Compounds Elements are represented by symbols Compounds are represented by chemical formula
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22. Chemical Formula of Compounds Rules: 4) Carbon Dioxide, C O 2 4) Oxygen is usually written at the end (except for hydroxide) 3) Water, H 2 O not H 2 O 1 3) Need not write subscript ‘1’ 2) Magnesium Carbonate, MgCO 3 2) Number of atoms is written on the right of the symbol 1) Calcium Oxide, Ca O 1) Metallic element is written first
23. Compounds Compounds can decompose into simpler substances when heat is applied Thermal Decomposition
24. Mixtures Two or more substances Added together Without chemical bonds being formed Impure Substances
25. Mixtures Can be made up of; Elements + Elements Alloys Elements + Compounds Air Compounds + Compounds Our Body
26. Mixtures S eparated by physical means Chromatography Filtration Distillation Crystallization