Chair Conformation evaluator to grade chemistry answers

Updated 30 Aug 2024

Use the Chair Conformation answer evaluator (expressionOchemEvalChair ) to check the number of times a group is axial or equatorial on a particular ring. The Chair Conformation evaluator works with the skeletal answer type.

  1. The Chair Conformation evaluator first looks for a six-membered ring in which all of the ring atoms are invisibly marked (that is, that the student copied from the Marvin JS templates, available in the bottom toolbar.)
  2. In the absence of a six-membered ring, the evaluator looks for any saturated cyclohexane ring. Exocyclic double bonds are allowed.
  3. In the absence of any saturated cyclohexane ring, it looks for a saturated six-membered ring with one heteroatom.
  4. In the absence of a saturated six-membered ring with one heteroatom, it looks for a saturated six-membered ring with any number of heteroatoms.
  • Your correct-response evaluator for a conformation question should be complex. For example, "If the answer is X or its enantiomer AND if the response has one axial Br group...."
  • If this evaluator is not satisfied, then write incorrect-response evaluators that test for various ways that the structure of the response may differ from X or its enantiomer.
  • For example, you may use the Is expression to test if the student has drawn an incorrect diastereomer, or if the student's response has the wrong formula.
  • Your last evaluator in this section should be, "If the response is not X or its enantiomer..." If the response does not satisfy this evaluator, then the response must have the right structure, but be in the wrong conformation.
  • You can use the conformation evaluators to determine how the conformation might be incorrect and provide appropriate feedback.

  1. Select Grade as Correct or Grade as Incorrect, then enter the conditions you want to be checked in student answers.
  2. Select the kind of bonds to check for, whether:
    • axial
      Six bonds parallel to the axis of the ring.
    • equatorial
      Six bonds along the equator of the ring.
  3. Enter the group.
  4. Select an “is” option.

    exactly
    Student answer number = the number in this box

    more than
    Student answer number > the number in this box

    fewer than
    Student answer number < the number in this box

    not exactly
    Student answer number <> the number in this box

    fewer than or equal to
    Student answer number ≤ the number in this box

    more than or equal to
    Student answer number ≥ the number in this box

  5. Enter the number of times the group is axial or equatorial.
  6. Select the following check box to account for cases in which a group is neither axial nor equatorial.

    "Override my feedback with automatically generated feedback if Mastering determines that a group is neither axial nor equatorial."

Select Show this response to enter wrong answer feedback for when the student’s answer matches a Grade as Incorrect condition.

Use your keyboard and options from the editing toolbar and menus. Wrong answer and follow-up text can include an image, link, and formatted text like bullets or TeX.

 

See also:

Answer evaluators list (for correct or incorrect answers) | How grading evaluators work | Properties for the Marvin JS drawing tool setup