solutionOchemMechanism

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This image shows the MarvinSketch chemical drawing tool with the beginning of a sample mechanism drawn on the canvas. Notice the mechanism toolbar for drawing boxes and reaction arrows. Toolbar buttons display their names when you point to them. (For instructions and videos about how to use MarvinSketch to draw mechanisms, click Help from the top menu.)

1. Create a new item.
   
2. Right-click inside the blue-border of the answer box. In the menu that opens, select Remove> solutionMultipleChoiceRadio.
3. Click the add link that appears inside a blue box and then select solutionOchemMechanism.
4. Enter information in the answer box, as described below. Clicking a red link opens a text entry field or checkbox for setting the value.

This option sets the size of the MarvinSketch window. Choose from:

• small (500 x 500 pixels) - The default. Generally used for a single-step mechanism.
• medium (850 x 600 pixels)
• large (850 x 750 pixels)

The default value, small, is generally used for a single step mechanism. Use medium and large for longer mechanisms. The larger size allows students to see the full preloaded figure (if one is used) or to draw the full mechanism without needing to scroll.

The Marvin Initialization Parameters control the behavior and display of MarvinSketch. These settings control which menu options are shown and/or what chemical information MarvinSketch automatically inserts (for example, Hydrogen atoms).

For information on setting these parameters, see Marvin Initialization Parameters.

• Pre-Text: Pre-Text can be used to write out the first step of a mechanism that the student answer completes. For example, Pre-Text can show the reactants in a reaction with an arrow pointing to the student response section where the students will enter the mechanism for the second step of that reaction to complete it.
• Post Text: Post-Text can complete a reaction, following the first step of a mechanism drawn by the students on the canvas

The Correct Answer box is used to display the molecule students will see if they click Give Up or Show Answer. The "Correct Answer" is for display purposes only and does not affect student grading.

Double-click in the Correct answer text box to draw the molecule in MarvinSketch. For details on how to enter a molecule in this box, see Adding Molecules for Comparison.

Expressions are evaluators that compare a student’s answer to a correct or wrong answer and give relevant feedback. For more information about expressions, see the following:

• Ochem expression reference table
• Key grading features of expressions
• How to add expressions
• Grade and response text fields
• Adding molecules for comparison (applies to the Contains and Is expressions)

For mechanism questions, code each condition that would make the answer wrong. After coding all possible wrong answers, add an expressionOchemEvalAtoms and set the number of carbon atoms to greater than 1. Using this method, a student will be marked correct if no error is made. This allows for multiple correct answers to be accepted.

See the "Add expressions" section above for instructions about adding evaluators that compare student answers to a correct or wrong answer and give relevant feedback.

MarvinView objects are Java applets that can be placed anywhere images can be inserted in an item. MarvinView molecules can be used as an interactive visual aid.

For example, students can rotate a molecule or make it spin in 3D. MarvinView objects can be used to help students answer a question or to reinforce their understanding, especially when provided in answer feedback. More about MarvinView interactive objects