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:
  $4NH<em>3 + 5O</em>2 \rightarrow 4NO + 6H_2O$
• From this balanced equation, various conversion factors (stoichiometric ratios) can be derived, such as:
  • $\frac{4 \text{ moles of } NH<em>3}{5 \text{ moles of } O</em>2}$
  • $\frac{5 \text{ moles of } O<em>2}{6 \text{ moles of } H</em>2O}$
  • $\frac{4 \text{ moles of } NH_3}{4 \text{ moles of } NO}$
• 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., $4 \text{ moles } NH<em>3 / 4 \text{ moles } NO$ instead of $1 \text{ mol } NH</em>3 / 1 \text{ mol } NO$). 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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