Grade 10 Science Chapter Notes PDF

Grade 10: Science 'S Chapter Notes JU BY  POST CLASS NOTES Chemical Reactions 'S JU and Equations BY 1  Chemical equation Chemical reaction Types...

Grade 10: Science 'S Chapter Notes JU BY  POST CLASS NOTES Chemical Reactions 'S JU and Equations BY 1  Chemical equation Chemical reaction Types 'S Effects JU BY Combination 1. Change in colour Thermal Decomposition Photolytic 2. Change in odour Electrolytic Single displacement 3. Change in state Double displacement 4. Heat transfer Redox Endothermic Exothermic 2  Chemical Reaction One or more participating substances transform to give new substances Involves a chemical change 'S Burning of magnesium JU Magnesium, Oxygen Magnesium oxide BY Photosynthesis Water, Carbon dioxide Glucose, Oxygen Respiration Glucose, Oxygen Carbon dioxide, Water 3  Effects of Chemical Reaction Chemical reactions involve one or more of the following: 1. Change in Colour Rusting of iron Leaves in fall 2. Change in Odour 'S JU Cooked food Spoiled fruit BY 3. Change in State Formation of Evolution of gas precipitate Mixing potassium iodide and lead nitrate Decomposition of lead nitrate on heating 4. Heat Transfer Endothermic: Exothermic: Cooking of food Absorption of heat Combustion Evolution of heat 4  Chemical Equation Short-hand representation of a chemical reaction Reactant 1 + Reactant 2 +... → Product 1 + Product 2 +…. 1. Burning of magnesium in oxygen is represented as: Magnesium + Oxygen → Magnesium oxide (Word equation) Mg + O2 → MgO 'S (Skeleton equation) JU 2. Photosynthesis is represented as: Carbon dioxide + Water → Glucose + Oxygen (Word equation) BY CO2 + H2O → C6H12O6 + O2 (Skeleton equation) Balanced Chemical Equation Total number of atoms of each Total number of atoms of each = element on the reactant side element on the product side Skeletal Equation Balanced Equation Mg + O2 → MgO 2Mg + O2 → 2MgO CO2 + H2O → C6H12O6 + O2 6CO2 + 6H2O → C6H12O6 + 6O2 5  Skeleton Equation to Chemical Equation solid (s) 1 2 liquid (l) Balance the equation gas (g) Mention physical state dilute (dil.) next to each concentrated (conc.) 3 formula aqueous (aq.) Mention reaction conditions precipitate (↓) above/below the arrow gas evolved (↑) Temperature Pressure 'S 4 JU Catalyst Mention energy transfer Light/hv Endothermic: Heat/ △ + Energy or Heat on reactant side BY Exothermic: + Energy or Heat on product side 1. Photosynthesis light 6CO2 (g) + 6H2O (l) C6H12O6 (aq) + 6O2 (g) 2. Formation of Ammonia 450o C, 250 atm N2 (g) + 3H2 (g) Fe catalyst 2NH3 (g) 6  Types of Chemical Reactions 1. Combination Reaction Two or more reactants give single product A + B A B 2Mg (s) + O2 (g) 2MgO (s) 2. Decomposition Reaction 'S Single reactant breaks down into two or more products Heat/Light/ JU Electrici ty A B A + B Thermal Heat BY (in presence of heat) 2Pb(NO3)2 (s) 2PbO (s) + 4NO2 (g) + O2 (g) Light Photolytic 2AgCl (s) 2Ag (s) + Cl2 (g) (in presence of light) Electricity Electrolytic (in presence of electricity) 2H2O (l) 2H2 (g) + O2 (g) 3. Single displacement reaction An element displaces another element from its compound A + B C A C + B Zn (s) + CuSO4 (aq) ZnSO4 (aq) + Cu (s) 7 4. Double displacement reaction Exchange of ions between the reacting compounds A B + C D A D + B C 2KI (aq) + Pb(NO3)2 (aq) 2KNO3 (aq) + PbI2 (s) 5. Redox (Reduction-Oxidation) reaction Oxidation: 'S Single reactant breaks down into two or more products Reduction: JU Gain of oxygen, or Loss of oxygen, or loss of hydrogen gain of hydrogen BY Always occur simultaneously Redox One reactant undergoes reduction while, the other undergoes oxidation Loss of oxygen: Reduction ZnO is reduced ZnO + C Zn + CO C is oxidised Gain of oxygen: Oxidation Loss of oxygen: Reduction MnO2 is reduced MnO2 + 4 HCl MnCl2 + 2 H2O + Cl2 HCl is oxidised Loss of hydrogen: Oxidation 8  Mind Map Short-hand representation of chemical reactions using symbols Chemical equation and chemical formulae Reactant → Product Chemical reaction Formation of new substance Types 'S Involves chemical change Effects JU Combination A + B A B 1. Change in colour BY Heat Thermal A B A + B Electricity 2. Change in odour Decomposition Electrolytic A B A + B Light + Photolytic A B A B 3. Change in state Single displacement A + B C A C + B 4. Heat transfer Double displacement A B + C D A D + B C Endothermic Exothermic One reactant undergoes reduction (addition of H or removal of O) while Redox the other undergoes oxidation (addition of O or removal of H) 9