Chemical Reactions and Equation-3

• Chemical Reactions

  • Burning of magnesium: Magnesium + Oxygen → Magnesium oxide
  • Photosynthesis: Water + Carbon dioxide → Glucose + Oxygen
  • Respiration: Glucose + Oxygen → Carbon dioxide + Water
• Change in odour
• Change in state
• Chemical Reaction


  1. One or more participating substances transform to give new substances

  2. Involves a chemical change
• Exothermic: Evolution of heat
• Change in colour
• Effects of Chemical Reaction involve:
• Chemical Reactions

  • Effects
  • Types
• Skeleton Equation to Chemical Equation

  1. Balance the equation

  2. Mention physical state next to each formula

  3. Mention reaction conditions above/below the arrow
• Endothermic: Absorption of heat
• Chemical Equation


  Short-hand representation of a chemical reaction
• Types of Chemical Reactions

  Combination Reaction: Two or more reactants give single product
• Effects of Chemical Reaction

  • Change in Colour
  • Change in Odour
  • Change in State
  • Heat Transfer
• Types of Chemical Reactions

  • Combination
  • Decomposition
  • Single displacement
  • Double displacement
  • Redox
• Heat transfer
• Skeleton Equation to Chemical Equation

  • Photosynthesis: 6CO2 (g) + 6H2O (l) → C6H12O6 (aq) + 6O2 (g)
  • Formation of Ammonia: N2 (g) + 3H2 (g) → 2NH3 (g)
• Mention energy transfer
• Types of Heat Transfer

  • Thermal
  • Photolytic
  • Electrolytic
  • Endothermic
  • Exothermic
• Balanced Chemical Equation

  Total number of atoms of each element on the reactant side = Total number of atoms of each element on the product side
• Single displacement reaction

  An element displaces another element from its compound
• Double displacement reaction

  Exchange of ions between the reacting compounds
• Types of Effects

  • Change in colour
  • Change in odour
  • Change in state
  • Heat transfer
• Chemical equation

  Formation of new substance involving chemical change
• Exothermic reaction

  • Energy or Heat on product side
• Redox (Reduction-Oxidation) reaction

  One reactant undergoes reduction while the other undergoes oxidation
• Oxidation


  Gain of oxygen, or loss of hydrogen
• States of matter abbreviations

  • solid (s)
  • liquid (l)
  • gas (g)
  • dilute (dil.)
  • concentrated (conc.)
  • aqueous (aq.)
  • precipitate (↓)
  • gas evolved (↑)
• Reduction

  One reactant undergoes reduction (addition of H or removal of O) while the other undergoes oxidation (addition of O or removal of H)
• Types of Chemical Reactions

  • Combination Reaction
  • Decomposition Reaction
  • Single displacement reaction
  • Double displacement reaction
  • Redox (Reduction-Oxidation) reaction
• Mind Map


  Short-hand representation of chemical reactions using symbols and chemical formulae
• Decomposition Reaction


  Single reactant breaks down into two or more products
• Effects of Chemical Reactions

  • Change in colour
  • Change in odour
  • Change in state
  • Heat transfer
• Reduction


  Loss of oxygen, or gain of hydrogen
• Combination Reaction

  Two or more reactants give single product
• Redox

  One reactant undergoes reduction while the other undergoes oxidation