Conformation: Newman Projections and the Chair · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Twists, chairs, and favourite shapes

Science · Chemistry · ages 18-19
Name ______________________   Date ____________

  1. Which arrangement rests in the valley and which perches on the peak?

    • Staggered sits low and eclipsed sits high
    • Eclipsed sits low and staggered sits high
    • Both always sit at equal energy

  2. In a Newman projection, what do the dot and the circle stand for?

    • The circle is the near carbon
    • The dot is the far carbon
    • The dot is near and the circle is far

  3. The cyclohexane chair has its corners alternating up and down.

    Circle one:   True   False

  4. What does a cyclohexane ring flip do to the positions?

    • It flattens the ring for good
    • It breaks one carbon bond briefly
    • It swaps every axial with an equatorial

  5. Which butane minimum sits lowest?

    • Gauche, with the methyls side by side
    • Anti, with the methyls opposite
    • Eclipsed, with the methyls aligned

  6. Methylcyclohexane flips between two chairs. Which one wins?

    • The chair with methyl equatorial
    • The chair with methyl axial
    • Both chairs equally, by symmetry

  7. Can you bottle the gauche form of butane like a separate compound?

    • No, conformations interconvert in a flash
    • Yes, freezing always works
    • Yes, if you cool below zero

  8. A student labels the butane profile with gauche below anti. Which statement about the true profile is correct?

    • Anti is a valley and eclipsed is a peak
    • Gauche sits lower than anti
    • Eclipsed methyls aligned are the lowest valley
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Answer key

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

Twists, chairs, and favourite shapes W1-mt_N0_QpGF7Av-s1

  1. Staggered sits low and eclipsed sits high · Spread out bonds relax, lined up bonds strain.
  2. The dot is near and the circle is far · Dot in front, circle behind: that is the viewing convention.
  3. True · Alternating corners dodge both angle and twisting strain.
  4. It swaps every axial with an equatorial · Up becomes out and out becomes up at every carbon.
  5. Anti, with the methyls opposite · Opposite methyls relax, side by side methyls clash.
  6. The chair with methyl equatorial · Equatorial points outward, dodging the steric crowding.
  7. No, conformations interconvert in a flash · Twists are fleeting, unlike locked cis trans forms.
  8. Anti is a valley and eclipsed is a peak · Valleys are staggered, peaks are eclipsed.
Worksheet · LightMySky