CHF Chemistry WebQuest #3 - Teacher's Guide Powered by Chemistry < Back | Home | Student Version | Next >

Purpose

The purpose of this WebQuest is twofold. First, it aims to demonstrate the tremendous relevance of chemistry to our everyday lives and the issues that face the world. Second, it aims to reinforce many basic chemistry concepts by demonstrating them in action. For the first goal, this WebQuest explores the chemistry behind the energy we use in all its variety. It also explores the consequences of our choices with regard to which chemistry we choose to employ to generate our energy. The issues surrounding the energy we use and its sources are contentious, and how we choose to answer the dilemmas these issues present may have far-reaching and long-lasting consequences. A thorough understanding of these issues is important for future voters and leaders who eventually will be making the very tough decisions these dilemmas require.

In order to reinforce the students' knowledge and skills, many basic chemistry concepts are involved in the research topics of this WebQuest.

Thermodynamics
Chemical reactions and reaction products
Electrochemistry
Nuclear chemistry
States of matter

Thermodynamics

First and foremost, this activity reinforces the relationship between energy and chemical change. Chemistry is not only the study of matter and the changes it undergoes, but it is also the study of the energy involved in those changes. Chemical reactions are either exothermic or endothermic, and it is the harnessing of exothermic processes that are of concern in this activity. Understanding the exothermic nature of the processes involved in all energy production is central to this WebQuest.

Chemical Reactions and Reaction Products

An understanding of chemical reactions and reaction products is important to this activity. Several of the questions deal with the production or burning of fuels. In both cases, chemical reactions and reaction products are involved. In the burning of fuels, the fuel reacts with oxygen, and the resulting products are of great importance as they may be benign (like water from burning hydrogen) or they may be hazardous (like carbon monoxide from burning organic fuels). This result must be taken into account when considering alternative fuels. The production of fuels also involves chemical reactions and their products. There are several methods of producing hydrogen, a potential fuel for both fuel cells and internal combustion engines. While the use of hydrogen as fuel produces only water as a reaction product, not all methods of hydrogen production are so harmless. Hydrogen can be produced by the electrolysis of water, essentially the reverse process of that which acts in fuel cells. However, methods that produce hydrogen by breaking down hydrocarbons also are being proposed for large-scale production. These processes produce carbon dioxide as a waste product, which is a greenhouse gas. Clearly, understanding reactions and reaction products is central to sorting out the issues involved in the quest for long-term energy solutions.

Electrochemistry

Electrochemistry, specifically oxidation-reduction processes, is pivotal to several of the questions in this WebQuest. Obviously, since electrical energy is so central to modern life, electrochemistry is going to play a crucial role in energy technologies. Three technologies addressed in this activity are based on redox processes, namely batteries, photovoltaic cells, and fuel cells.

Nuclear Chemistry

Nuclear chemistry can be explored by studying the fission reactions used to produce electricity today and the fusion reactions that may be harnessed in the future for generating electricity. The students should be aware that the same fusion of hydrogen nuclei to form helium nuclei powers the sun.

States of Matter

Exploration of particulate matter pollution, often produced by burning organic fuels, can reinforce understanding of the states of matter. It is important that students learn the differences between gas-phase pollutants, such as carbon monoxide, and the finely dispersed liquid and solid pollutants that we call particulate matter.

Carrying out the Activity

To perform this activity, divide the class into teams. The number of people on each team will depend on the number of students in your class. Strategies for ensuring each student does a fair share of the team's work vary. For example, if you assign an oral presentation of the student reports, you may assign each student to make part of the presentation. In this case, each student might be responsible for presenting the answers to one of the questions listed in the "Process" section of the student page. Alternatively, you might assign different team members the jobs of preparing the written, oral, and electronic reports. Other strategies are possible and their use is left to your own discretion.

The WebQuest asks the students to prepare some sort of report based on their investigations. You may choose to assign your students to write a paper, to prepare an oral presentation, or even to create a Web page. You may also choose to assign any combination of the three. In evaluating the reports, you may choose to use this scorecard as your rubric, or you may choose some other method of assessing student performance.

To conclude the activity, you may carry out a group discussion in class on the students' findings. You may conduct this in conjunction with oral presentations if you choose to assign them. In carrying out the discussion, try to show the students how to use their scientific and technological understanding to help them approach the difficult social, political, and environmental issues surrounding energy use. Some questions you may propose are:

What obstacles are keeping people from using cleaner energy sources?

What does the ever-changing price of oil have to do with efforts to switch to cleaner energy sources?

Who benefits when we switch from one energy source to another? Who suffers?

How does our choice of energy sources affect national security and foreign policy?

Relevant National Science Education Standards

Unifying Concepts and Processes—The investigation topics require the understanding of several diverse chemical systems and their components.

Physical Science—The electronic structure of atoms, the molecular nature of matter, chemical reactions, and the interactions of energy and matter are central to this activity.

Earth and Space Science—One topic of investigation looks at how our use of energy affects geochemical cycles, specifically the carbon cycle.

Science and Technology—The activity explores the capabilities of current technology to meet our energy needs, its limitations, and the possibilities offered by future technologies. In addition, technical understanding of these technologies is gained though the activity.

Science in Personal and Social Perspectives—The issues surrounding energy use necessarily involve questions concerning natural resources, environmental quality, human-induced hazards resulting from energy technologies, and the role of science and technology in meeting local, national, and global challenges posed by our need for energy and the consequences of energy use.

History and Nature of Science—One investigation topic looks at the history of gasoline in the twentieth century with regard to lead-based additives and the catalytic converter.

This CHF Chemistry WebQuest was created by Mark Michalovic.