June 2023 NY Regents Chemistry Exam
45 Given the formula representing a compound:
What is a chemical name of this compound?
(1) 1,1-dibromopentane
(2) 2,2-dibromopentane
(3) 1,2-dibromopentane
(4) 4,5-dibromopentane
Solution: The structure of the molecule has carbons and hydrogens representing an organic molecules. We see all single bonds which means this is an alkane. The name must end in "ane". Next, we find the longest carbon chain. In this case, it is five carbons. Table P on the reference table shows that the prefix for five carbons is pent, making the parent chain pentane. Finally, we number the carbons from the end closest to bromine, from the left. There are two bromines, one on the first carbon and another on the second. The numbers in front of the molecule represent the carbons to which bromines are attached.
Answer: 3
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