Mechanism Counter evaluator to grade chemistry answers

Updated 30 Aug 2024

Use the Mechanism Counter answer evaluator (expressionOchemEvalMechCounter) to compare the number of boxes, reaction arrows, or resonance arrows in a student’s answer to the expected number of boxes, reaction arrows, or resonance arrows in a mechanism question.

  1. Select Grade as Correct or Grade as Incorrect, then enter the conditions you want to be checked in student answers.
  2. Select an “if” condition.
    ConditionDescription
    boxesRectangle that contains each step of a mechanism.
    reaction arrows

    A reaction arrow connects two boxes in a mechanism. The arrow is a straight arrow that points to the right.

    This arrow is available from the left toolbar in a mechanism question.

    reaction and resonance arrows
    • For reaction arrows, see above.
    • A resonance arrow is a 2-headed arrow that points to the right and left. This arrow is available from the left toolbar in a mechanism question.
  3. Select an "is" condition.

    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

  4. Enter the number of boxes, reaction arrows, or reaction and resonance arrows for which to evaluate.

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