The Chair Confirmation expression
The Chairs expression (expressionOchemEvalConformChair) checks the number of times a group is axial or equatorial on a particular ring.
- The Chair Confirmation evaluator first looks for a six-membered ring in which all of the ring atoms are invisibly marked (i.e., that the student copied from the MarvinSketch Templates menu.)
- In the absence of a six-membered ring, the evaluator looks for any saturated cyclohexane ring. Exocyclic double bonds are allowed.
- In the absence of any saturated cyclohexane ring, it looks for a saturated six-membered ring with one heteroatom.
- 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 response 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.
| Menu Option |
Description |
| Axial |
Six bonds parallel to the axis of the ring. |
| Equatorial |
Six bonds along the equator of the ring. |
| Menu Option |
Mathematical Equivalent |
| Exactly |
student number = author number |
| More Than |
student number > author number |
|
Fewer Than
|
student number < author number
|
| Not Exactly |
student number <> author number
|
| Fewer Than or Equal To |
student number <= author number
|
| More Than or Equal To |
student number >= author number |
See also:
Expressions overview (Ochem answer types)
Working with Ochem expressions
How the evaluator for this expression works