Stoichiometry and Chemical Formula Calculations

Stoichiometry and Formula Calculations

Conversion Factors from Balanced Equations

  • Balanced chemical equations provide intensive conversion factors in the form of stoichiometric ratios.
  • These ratios relate the molar quantities of reactants and products.
  • Example Balanced Equation:
    4NH3 + 5O2 \rightarrow 4NO + 6H_2O
  • From this balanced equation, various conversion factors (stoichiometric ratios) can be derived, such as:
    • \frac{4 \text{ moles of } NH3}{5 \text{ moles of } O2}
    • \frac{5 \text{ moles of } O2}{6 \text{ moles of } H2O}
    • \frac{4 \text{ moles of } NH_3}{4 \text{ moles of } NO}
  • Important Note: It is crucial to use the exact coefficients from the balanced equation when writing these ratios, even if they simplify to smaller whole numbers (e.g., 4 \text{ moles } NH3 / 4 \text{ moles } NO instead of 1 \text{ mol } NH3 / 1 \text{ mol } NO). This ensures clarity and traceability of the ratios.
  • Nature of Ratios: These ratios are mole-to-mole ratios, not gram-to-gram ratios. It is a common mistake to treat them as gram ratios.

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