Lecture Notes: Understanding Chemical Equations

Introduction to Chemical Equations

• Chemical equations represent chemical reactions.
• Structure of Equations:
  • Reactants: Left side of the equation (starting substances).
  • Products: Right side of the equation (substances formed).

Symbols in Chemical Equations

• Plus Sign (+): Separates different compounds or elements.
• Reaction Arrow (→): Indicates reactants form products.
• Physical States:
  • (s): Solid
  • (l): Liquid
  • (g): Gas
  • (aq): Aqueous (dissolved in water)

Additional Indicators

• Conditions Over the Arrow:
  • Example: Delta (Δ) indicates heat is applied.
  • Other symbols can specify conditions necessary for reactions without being reactants or products (e.g., sunlight).

Coefficients in Chemical Equations

• Numbers in front of formulas indicate quantity:
  • E.g., 2 Na + Cl₂ → 2 NaCl.
  • Indicates ratio of molecules and atoms involved.

Balancing Chemical Equations

• Count atoms/ions on each side:
  • Make a division at the arrow to separate reactants from products.
  • Example: 2 Na + Cl₂ → 2 NaCl
    • 2 sodium atoms and 2 chlorine atoms on both sides.

Law of Conservation of Matter

• Matter cannot be created or destroyed in reactions.
• Equations must be balanced to reflect this law:
  • Equal numbers of each element on both sides of the equation.

Future Topics

• Balancing techniques will be explored in detail in future lectures.