CHE 232-001

Facts and Skills to Master for the First Exam

The first exam will cover Klein Chapters 1–11 and 14–15. The following guidelines are not meant to be complete or comprehensive lists of the information you are expected to know.

You are expected to have command of all the material covered in CHE 230.

You should be able to draw a variety of structures that are consistent with a formula.

You should be able to propose one or more formulas for a compound that are consistent with its MS spectrum.

You should be able to draw one or more structures for a compound that are consistent with its formula and its IR spectrum.

You should understand how the NMR experiment works and what factors affect a H or C atom's chemical shift and multiplicity.

You should be able to determine which H or C atoms in a structure are equivalent (homotopic, enantiotopic, exchangeable by rotation) or not, and label them accordingly.

You should be able to draw a structure of a compound that is consistent with its formula and 1H or 13C NMR spectra. Also, given a description of a chemical reaction [that was covered in CHE 230] and the 1H or 13C NMR spectra of the product(s), you should be able to draw the structure of the product(s).

Given a sample of a compound that has one of two possible structures, you should be able to propose a spectroscopic test that would tell you unambiguously whether the compound has one or the other structure.

Advice on how to answer this kind of problem.
  1. Use the word "whereas" in your response to make sure that you are contrasting the spectra of the two compounds.
  2. Your response must refer to specific features of the MS, IR, or NMR spectrum of a compound. It is not correct to say, "The compound on the left has Cl, whereas the compound on the right doesn't." It is correct to say, "If I have the compound on the left, I will see an M+2 peak in the MS spectrum, whereas if I have the compound on the right, I will not."
  3. You have only one sample, so your response cannot rely on a comparison of spectra. For example, this response is incorrect: "The compound on the left will have a peak in its 1H NMR spectrum that is further downfield than any peak in the 1H NMR spectrum of the compound on the right." Instead, you need to propose a feature that will be present if the compound has one structure and different or absent if it has the other. For example, this response is good: "The 1H NMR spectrum of the compound on the left will have a peak that is in the range of 3.5–4.5 ppm, whereas the 1H NMR spectrum of the compound on the right will not."

You should be able to predict the approximate chemical shift, integration, and multiplicity of each kind of H atom in a compound's 1H NMR spectrum. You should also be able to predict the approximate chemical shift of each kind of C atom in a compound's 13C NMR spectrum.