which information must be known about a compound to find the molecular formula from the empirical…

which information must be known about a compound to find the molecular formula from the empirical formula?\n- density\n- formula mass\n- percent composition\n- mole ratio

which information must be known about a compound to find the molecular formula from the empirical formula?\n- density\n- formula mass\n- percent composition\n- mole ratio

Answer

Answer:

B. formula mass

Explanation:

Step1: Recall the relationship

The molecular formula ($MF$) and empirical formula ($EF$) are related by $MF=(EF)_n$, where $n = \frac{\text{molar mass of compound}}{\text{molar mass of empirical - formula}}$. The molar mass of a compound is related to its formula mass.

Step2: Analyze each option

  • Density is not used in the calculation to get from empirical to molecular formula.
  • Percent - composition is used to find the empirical formula, not to get from empirical to molecular formula.
  • Mole ratio is part of the empirical formula itself and not what is needed to convert to molecular formula.
  • The formula mass (or molar mass) of the compound and the empirical formula is needed to find the factor $n$ to convert the empirical formula to the molecular formula.