Chem

• red: acidic

  green: neutral

  purple: alkaline

  
• Fe2+: green

  Fe3+: yellow/brown
• Endothermic:

  • Cracking
  • Thermal decomposition
  • Ionisation of water
  • Dissolving ammonium nitrate in water
  • Boiling
  • Evaporation
  • Sublimation
  • Melting
• Exothermic:

  • Neutralisation
  • Displacement reaction
  • Combustion
  • Precipitation
  • Preaction of K/Na/Ca/CaO with water
  • Fermentation of glucose
  • Dissolving acids, alkalines in water
  • Freezing
  • Condensation
• Methyl orange:

  • Addition of acid: yellow to orange
  • Addition of alkaline: red to orange
• Nitrite: NO₂⁻

  Nitrate: NO₃⁻

  Nitride: N³⁻
• Hydrogencarbonate: HCO3 -

  Carbonate: CO3 2-
• Sulphide: S 2-

  Sulphite: SO3 2-

  Sulphate: SO4 2-