1.5: Chemical Formulas in WeBWorK

Background on Displaying Chemical Formulas

For chemical formulas, we will use mhchem for MathJax to render our formulas.

Read more here: LibreTexts Construction Guide Adding and Editing Equations

Displaying the Chemical Formulas

For chemical formulas, we will use mhchem for MathJax to render our formulas.

$question = "In the following chemical reaction for cellular respiration, which reactant is being oxidized?
$BR
\[ \ce{C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O} \]";

The final line of our question variable has the chemical equation for cellular respiration:

\[ \ce{C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O} \]

The chemical formula is contained within the \ce{ } denoting it as a chemical formula. The \[ and \] symbols indicate that the chemical equation should be displayed on its own line. It will render like this:

\[ \ce{C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O} \nonumber \]

Putting It All Together

DOCUMENT();
loadMacros(
  "PGstandard.pl",    # Standard macros for problem grading
  "parserRadioButtons.pl",  # Macros for creating radio button inputs
);

### BEGIN QUESTION SETUP

# Define the question and options
$question = "In the following chemical reaction for cellular respiration, which reactant is being oxidized?
$BR
\[ \ce{C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O} \]";

@options = ("\( \ce{C6H12O6} \)", "\( \ce{O2} \)", "\( \ce{CO2} \)", "\( \ce{H2O} \)");   # Options presented to the student

# Define the correct answer
$correct_answer = "\( \ce{C6H12O6} \)";   # Correct option among the provided choices

### END QUESTION SETUP

TEXT(beginproblem());

# Setup radio buttons for the choices
$radio = RadioButtons(
    [@options],   # Array reference to the list of options
    $correct_answer,   # Specify which option is correct
    labels => "ABC",   # Label the choices with letters for clarity
    displayLabels => 1,   # Enable display of labels next to radio buttons
    separator => '<div style="margin-bottom: 0.7em;"></div>',   # Add custom spacing for better readability
    uncheckable => 1,   # Allow students to uncheck an option by re-clicking
    randomize => 1,   # Randomize the order of options to prevent answer pattern guessing
);

# Display the question and radio buttons
BEGIN_TEXT
<p>\{ $question \}</p>  <!-- # Display the question text -->
\{ $radio->buttons() \}  <!-- #Display the radio buttons for answering-->
END_TEXT

# Evaluate the student's answer
ANS($radio->cmp());  # Compare the student's choice with the correct answer

### END CODE

ENDDOCUMENT();