Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Empirical formulas can be determined from the percent composition of a compound. In order to determine its molecular formula, it is necessary to know the molar mass of the compound. Chemists use an instrument called a mass spectrometer to determine the molar mass of compounds. In order to go from the empirical formula to the molecular formula, follow these steps:. Answer: molar mass
Output:
In order to determine its molecular formula, it is necessary to know what about the compound?