The Lecture on Chemical Equations and the Impact of Different Substances on Them

Introduction to Chemical Equations

• Definition of a Chemical Equation: Components that react with each other to produce new substances called products.
• Components of the Equation: Reactants and products.
• Substances: Composed of molecules, and molecules can consist of different or similar atoms.

Classification of Atoms and Molecules

• Elements: One atom or two similar atoms (Example: H2).
• Compounds: Two or more different atoms (Example: NaCl).

Interaction of Elements with Air

• Alkali Metals: Very reactive and easily lose electrons.
• Their reaction with air: They lose their shine due to the formation of an oxide layer.
• Oxide formation: The metal reacts with oxygen to form a layer of metal oxide.

Experiments on Alkali Metals Reactions with Air and Water

• Sodium's reaction with water:

  • Equation: Na + H2O → NaOH + H2
  • Produces heat (exothermic reaction).

• Reaction of different metals with oxygen:

  • Lithium at 180°C: Li + O2 → Li2O
  • Sodium at 300°C: Na + O2 → Na2O2
  • Potassium at 300°C: K + O2 → KO2

Impact of Water and Air on Alkali Metals

• Alkali metals reaction with water: Produces hydrogen gas and high heat (Example: Sodium's reaction with water).
• Storing alkali metals: Stored under kerosene to prevent them from reacting with air.

Alkali Metals Reactions with Hydrogen and Acid

• Alkali metals reaction with hydrogen: Formation of hydrides.
• Alkali metals reaction with acid: For example Na + HCl → NaCl + H2.

Alkali Metals Reactions with Non-Metals

• Non-metals: Examples of reactions with fluorine and chlorine.
• Reaction equations:
  • Na + Cl2 → NaCl
  • K + Br2 → KBr

Impact of Heat on Carbonates and Nitrates

• Carbonates:

  • All alkali metal carbonates dissolve except lithium carbonate which decomposes with heat.

• Nitrates:

  • Sodium nitrate converts to sodium nitrite (NaNO2 → NaNO3 + O2).
  • Potassium nitrate converts to potassium nitrite (KNO2 → KNO3 + O2).

Applications of Chemical Reactions

• Using Super Oxides as oxygen generators in submarines and airplanes.

Additional Notes

• The importance of memorizing equations and repetitive review.
• The use of some chemical substances in daily life, such as potassium nitrate in fireworks.