Periodic Table and Periodicity

PlantUML Diagram

III. Molecular Mass and Formula Mass:

A. Molecular Mass:

Definition: Sum of atomic masses of all atoms in a molecule.
Calculation method: Add up atomic masses of all atoms.
Example: Water (H₂O) = 2(1.008) + 16.00 = 18.016 amu

B. Formula Mass:

Used for: Ionic compounds
Definition: Sum of atomic masses of all atoms in the formula unit.
Example: Sodium Chloride (NaCl) = 23 + 35.5 = 58.5 amu

IV. Examples and Exercises:

A. Determining Molecular Mass:

  • Glucose (C₆H₁₂O₆) = 180.096 amu
  • Naphthalene (C₁₀H₈) = 128.00 amu

B. Determining Formula Mass:

  • Sodium Chloride (NaCl) = 58.5 amu
  • Magnesium Hydroxide (Mg(OH)₂) = 58 amu

C. Practice Problems:

  • Calculate formula mass for:
    • Potassium Chlorate (KClO₃)
    • Sodium Bicarbonate (NaHCO₃) and Carbon Dioxide (CO₂)
    • Urea ((NH₂)₂CO) and Ammonium Nitrate (NH₄NO₃)

Note: This unit covers the fundamental concepts of chemical formulas, molecular and formula mass calculations. It provides a foundation for understanding chemical composition and stoichiometric calculations. The content includes definitions, examples, and practice exercises to reinforce learning.