Module 1

Module 1—Thinking Energy

Lesson 6—Communicating Enthalpy Change

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Campfires are a common sight on ecotours. They are a means of cooking food, providing warmth, and inspiring stories. Fire involves a combustion reaction—one of the most common exothermic reactions.

As a science student you have been taught to observe chemical reactions for evidence of change, including energy change. What kinds of energy changes are occurring during a combustion reaction? In some reactions you can feel an increase in temperature or see light emitted.

In previous lessons you learned to quantify the energy change, as heat, associated with a chemical reaction. In this lesson you will further expand your understanding of enthalpy change. You will investigate how each of the following methods allows a process' enthalpy change to be clearly identified and associated with a specific chemical reaction:

• molar enthalpy of reaction for a specific reactant

• enthalpy change for a balanced reaction equation

• inclusion of the energy as a term in a balanced reaction equation

• chemical potential energy diagrams

Consider the following question as you complete Lesson 6:

• How are enthalpy changes communicated?

Module 1: Lesson 6 Assignment

There is no assignment for this lesson. However, you will be asked to submit samples of your work to your teacher for feedback where instructed.

In Lesson 8 you will complete an assignment on material covered in Lessons 6, 7, and 8. In preparation for the Lesson 8 Assignment, you may wish to summarize what you learn in Lessons 6, 7, and 8 as you proceed through these lessons. Your summary may take one of many forms (e.g., list, outline, concept map), depending on your individual learning style. Save a copy of your summary in your course folder so that you may quickly add to and review your summary in preparation for the Lesson 8 Assignment.

You must decide what to do with the questions that are not marked by the teacher.

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.