Imat 2013 q 47 Chemistry/isomer conditions

Practice Question Solving
1

The answer says E, but arent steroisomers same in both molecular and structural, while differing only in spatial arrangements so why isnt it D?

Which of the following must be correct about organic isomers?

  1. They have the same molecular formulae.
  2. Their physical properties are very similar.
  3. They have different structural formulae.

A. 1 and 2 only
B. 1, 2 and 3
C. 2 and 3 only
D. 1 only
E. 1 and 3 only

2

Hi!

you’re right but it’s not in the 2022 test specification
so we don’t consider stereoisomers
correct me if i’m mistaken, i also haven’t seen past questions on geometric and optical isomers

3

yep no question on geo/optical

4

Hi!
Idk tbh but its a bit weird cuz that would mean u have to remember the spec. In the exam.

5

yes, this question is not about stereoisomers just the structural ones. So since their structure is different, the way their bonds interact is different, so it could have different physical properties (more branching - lower boiling points due to increased surface area). Their structural formulas are different as there could be methyl groups placed on different carbons. However molecular formulae would stay the same as the total number of elements involved would be the same. Hope this helps! In terms of stereoisomers I believe it’s good to just know the difference between cis and trans isomers and the optical isomers (symmetry etc.)

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