Formula evaluator to grade chemistry answers

Updated 30 Aug 2024

Use the Formula answer evaluator (expressionOchemEvalFormula) to convert the student’s response into a chemical formula and compare it to the evaluator formula. Both skeletal and mechanism questions support the Formula evaluator.

Select Grade as Correct or Grade as Incorrect, then enter the conditions you want to be checked in student answers.
Select an “if” condition.
"If" condition options
the response has
The whole student’s answer has the same formula as the formula in this evaluator.
the response doesn't have
The whole student’s answer does not have the same formula as the formula in this evaluator
the number of compounds in the response that have
Compares the formulas of each compound in the student’s answer to the formula in this evaluator. Then, it sums the number that matches and compares it to an integer with the formula in the molecular formula box.
the number of compounds in the response that don’t have
Compares the formulas of each compound in the student’s answer to the formula in this evaluator. Then, it sums the number that doesn’t match and compares it to an integer with the formula in the molecular formula box.
Enter a single formula in plain text. For example, H₂0 should be entered as H20.
If you selected either the number of compounds in the response that have or the number of compounds that don’t have in step 2, select an “is” option and enter the number of compounds in the last box.
“Is” options
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