Structure Elucidation from a Complete Data Set · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Many spectra, one structure

Science · Chemistry · ages 22-23
Name ______________________   Date ____________

  1. What do radio waves probe in an NMR experiment?

    • Bond vibrations in the infrared range
    • The spacing of crystal layers
    • Nuclear spin flips that report atom surroundings

  2. An infrared trace shows a strong O-H band. What does that band tell you?

    • Which functional groups are present
    • The exact count of every atom
    • The crystal space group

  3. One infrared spectrum is usually enough to settle a whole structure.

    Circle one:   True   False

  4. A compound has formula C6H12 (ignore oxygen-style atoms here; none are present). How many degrees of unsaturation does it have?

    Answer: ______________

  5. A formula gives 1 degree of unsaturation. What must the structure contain?

    • Exactly one ring and one pi bond
    • One ring or one pi bond
    • No rings and no pi bonds

  6. Which order spends the evidence cheapest first?

    • Full NMR set, then infrared, then formula
    • Infrared, then formula, then full NMR set
    • Formula, then infrared, then full NMR set

  7. A compound has formula C6H6. How many degrees of unsaturation must its structure spend?

    Answer: ______________

  8. Two candidates survive, and a correlation map ties two atoms together that stay apart in candidate X. What follows?

    • Candidate X gains support, since maps can be reread
    • Both candidates survive, since one tie proves little
    • Candidate X is ruled out by that datum
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Many spectra, one structure W1-mt_O2uungksMZ-s1

  1. Nuclear spin flips that report atom surroundings · Radio waves flip nuclear spins, a different feature than bond vibrations.
  2. Which functional groups are present · Characteristic infrared frequencies name the vibrating bonds and their groups.
  3. False · Each region sees one feature, so several techniques must combine.
  4. 1 · Six carbons plus one minus half of twelve hydrogens leaves 1.
  5. One ring or one pi bond · Each degree is spent as one ring or one pi bond.
  6. Formula, then infrared, then full NMR set · Cheap facts prune candidates before the dear maps are built.
  7. 4 · Six carbons plus one minus half of six hydrogens leaves 4.
  8. Candidate X is ruled out by that datum · A candidate that cannot explain a tie fails, leaving its rival standing.
Worksheet · LightMySky