Determine molecular formula

Cards (9)

  • What does the molecular formula represent?
    Actual number of atoms in a molecule
  • What are the differences between molecular and empirical formulas?

    • Molecular formula: Actual number of atoms
    • Empirical formula: Simplest whole number ratio
  • How does the empirical formula relate to the molecular formula?
    Empirical shows ratios; molecular shows amounts
  • What are the methods to determine molecular formula?
    1. Empirical formula and molar mass
    2. Percent composition data
  • What is required to use the empirical formula and molar mass method?
    Empirical formula and molar mass of compound
  • What is the first step in determining molecular formula using empirical formula and molar mass?
    Calculate the molar mass of the empirical formula
  • How do you find the multiplier in the empirical formula and molar mass method?
    Divide compound's molar mass by empirical's molar mass
  • What are the steps to determine molecular formula using percent composition data?
    1. Convert percentages to grams
    2. Convert grams to moles
    3. Determine simplest mole ratio (empirical formula)
    4. Use molar mass to find multiplier
    5. Multiply empirical formula to get molecular formula
  • If a compound has 40% carbon, 6.7% hydrogen, and 53.3% oxygen, what is the first step in determining its molecular formula?
    Convert percentages to grams