Final answer:
To find the molecular formula from the vapor density, we first need the empirical mass (which seems to be missing). Vapor density is half the molar mass, so if we had the empirical mass, we could multiply the empirical formula by the molar mass divided by the empirical mass to find the molecular formula. Without the correct empirical mass, we cannot determine the molecular formula for 'SR'.
Step-by-step explanation:
To determine the molecular formula of a compound when given the empirical mass and vapor density, one must first understand the relationship between these quantities. The problem states that the empirical mass is 0, which seems to be a typo since no compound can have a mass of 0. Assuming this was meant to be the empirical formula weight, and it has not been provided, we will treat 'SR' as the empirical formula symbol, not the actual elements involved. The vapor density of a gas is half the molar mass, hence the molar mass in this scenario is 15 x 2 = 30 g/mol. To find the molecular formula, we divide the molar mass by the mass of the empirical unit (which we need but is missing in the question) and multiply the empirical formula by this factor to get the molecular formula.
Taking a similar empirical formula 'BH₃' with a molar mass of 27.7 g/mol from the provided examples, we can demonstrate how to determine the actual molecular formula. Since the empirical formula mass of BH₃ is 13.84 g/mol (B = 10.81, H = 1.01 x 3), the ratio of the molar mass to the empirical formula mass is 27.7 / 13.84 = 2. Therefore, the molecular formula is B₂H₆. However, without the actual empirical mass for 'SR', we cannot complete the process for the original question.