Final answer:
To find the molecular formula, divide the given formula mass (26 g/mol) by the empirical formula mass (13 g/mol), which yields 2. Hence, the molecular formula of the compound is C2H2. Option B is correct..
Step-by-step explanation:
The student has asked about the determination of a molecular formula given that the compound's empirical formula is CH and the formula mass is 26 grams/mole. To figure out the molecular formula, we need to compare the empirical formula mass with the given formula mass.
The empirical formula CH consists of one carbon atom (approximately 12 g/mol) and one hydrogen atom (approximately 1 g/mol), which gives us an empirical formula mass of approximately 13 g/mol. The next step is to divide the formula mass of the compound by the empirical formula mass: 26 g/mol divided by 13 g/mol equals 2. This indicates that the molecular formula has twice as many of each element as the empirical formula.Therefore, the molecular formula is C2H2, which is option B). The molecular formula is a whole number multiple of the empirical formula, which, in this case, is 2 times CH (C1H1 x 2 = C2H2).