Final answer:
To find the molecular formula of a compound, you need the empirical formula and molar mass. Divide the molar mass by the empirical formula mass to find the integer multiple. Multiply the subscripts in the empirical formula by the integer multiple to get the molecular formula.
Step-by-step explanation:
To find the molecular formula of a compound, we need to know the empirical formula and the molar mass. The empirical formula gives the simplest whole-number ratio of atoms in a compound. The molar mass is the mass of one mole of a substance.
Part A: The empirical formula is C6H7N and the molar mass is 186.28 g/mol. To find the molecular formula, we need to calculate the empirical formula mass and divide the molar mass by it. The empirical formula mass is 95.13 g/mol. Dividing the molar mass by the empirical formula mass gives us 1.959. This means that the molecular formula is approximately 1.959 times the empirical formula, so the molecular formula is C13H14N2.
Part B: The empirical formula is C2HCl and the molar mass is 120.95 g/mol. The empirical formula mass is 49.47 g/mol. Dividing the molar mass by the empirical formula mass gives us 2.448. This means that the molecular formula is approximately 2.448 times the empirical formula, so the molecular formula is C4H2Cl2.
Part C: The empirical formula is C5H10NS2 and the molar mass is 593.11 g/mol. The empirical formula mass is 155.29 g/mol. Dividing the molar mass by the empirical formula mass gives us 3.82. This means that the molecular formula is approximately 3.82 times the empirical formula, so the molecular formula is C19H38N3S8.