Condensed structural formulas
You may want students to enter condensed structural formulas in response to certain questions as opposed to the standard chemical formula.
For example, the condensed 
versus the standard 
.
In this case, you code the condensed structural formula as the correct answer. In cases where the format does not matter, code both answers as correct answers with the standard formula listed first.
See also:
Entering solutionChemicalFormula answers
Generic incorrect answer responses