Final answer:
The identification number for the proper shipping name 'Nicotine' is not provided in the context, and such a number would typically be found in regulatory databases. For the molecular formula of nicotine, based on the empirical formula and molar mass, the molecular formula is C10H14N2.
Step-by-step explanation:
The identification number for the proper shipping name "Nicotine" refers to the UN or DOT number assigned to substances for transportation. This number is essential for anyone handling or shipping chemicals to know which guidelines to follow for the safe and compliant transportation of hazardous materials. However, the information provided does not include the actual identification number, and to provide an accurate response, one would need to refer to the appropriate databases or regulatory lists which categorize these substances. As such, it is not possible to give a specific number for nicotine without this external reference.
On the other hand, if the question relates to determining the molecular formula of nicotine, one could use the information provided. Given that nicotine contains 74.02% carbon (C), 8.710% hydrogen (H), and 17.27% nitrogen (N) and that there are 0.2500 moles in a 40.57 g sample, it is possible to calculate its empirical formula and then derive its molecular formula by comparing the molar mass with the empirical formula mass, which indicates that every molecule of nicotine contains two formula units.
If we start from the empirical formula C5H7N, and multiply each subscript by two as indicated, we get the molecular formula C10H14N2 for nicotine.