Heat of Formation - Directions

Using the Heat of Formation Concept Builder is quite simple. There are three different activities. In the first activity you are provided the value for the heat of formation of a compound. Six different chemical equations are also presented along with a ∆H value for each of the six reactions. Knowing what the heat of formation means (see the Help Me! page if you don't), you must decide which of the six equations and corresponding ∆H values are consistent with the heat of formation value. Tap on an equation to select it; it will be enclosed in a grey rectangle. Tap a second time to deselect it. Select all equations that apply. As long as you have at least one equation selected, a Check Answer button will be visible. When you are satisfied with your answer, tap on the Check Answer button. Your answers will be evaluted and the Progress Report will be updated (for Task Tracker users).

The second and third activities work differently than the first activity. In the Heat of Reaction 1 and Heat of Reaction 2 activities, you must ultimately determine the ∆H of a given reaction. You do so by using the ∆H_formation values for the compounds involved in the reaction. The ∆H_formation values are listed in the panel on the right side of the Concept Builder. Tapping on the panel closes it; tapping on the View ∆H_f Values button re-opens the panel. You accomplish the task in steps (2 steps for Heat of Reaction 1 and 3 steps for Heat of Reaction 2). The Concept Builder guides you through the process. The step is described (in the grey box near the bottom of the Concept Builder) and six answer options are provided. Tap on an Answer Option (text or button to its left) to select it. Tap on the Check button to check your answer. Feedback is given and multiple (endless) opportunities are allowed to get the answer correct. Once correct, the step is plotted on the graph and you will be guided through the second step (or the third step). Once you have completed the 2- or 3-step analysis, a summary is provided and you are instructed to use the values for ∆H of the steps to calculate the ∆H of the reaction. You are allowed only one attempt to do this; no grace here. Enter your answer using the number pad. Be sure to include the negative sign if the ∆H is negative. When satisfied with your entered value, tap on the Check Answer button. Your answer will be evaluated and your Progress Report will be updated.

Your goal is to earn "Stars" and to complete one or more activities. Stars are earned when you show success on a particular question. If you miss a question then you will have to answer two similar questions correctly before earning a star. Once you show success on all the questions for a particular activity, you will earn the trophy for that difficulty level (Task Tracker users only).