Chemical Changes

Introduction

What is a chemical change?

A chemical change is an irreversible change where all substances present at the beginning form a new substance. This webquest will help you understand what a chemical change is and will give some examples of chemical changes.

Task

Answer the PROCESS questions and do the PROCESS activities about chemical changes. Use the links provided to help you complete the tasks. There are a couple of quizzes and a few videos to help you understand chemical changes. You will then be able to test your understanding in the EVALUATION section.

Process

Answer these questions by using the provided links and videos below.

1. What is a chemical change?

2. What are some examples of chemical changes?

3. What are some examples of evidence of chemical changes?

Use these links to help you answer the questions above:

http://chemistry.about.com/od/matter/a/10-Chemical-Change-Examples.htm

http://antoine.frostburg.edu/chem/senese/101/matter/faq/physical-chemical.shtml

http://www.chem4kids.com/files/matter_chemphys.html

http://www.ric.edu/faculty/ptiskus/chemical/

https://docs.google.com/presentation/d/1anYDOWRfkHddy5PrkANUC32eryOz07Rc64xFvb5JgyM/embed#slide=id.i0

This video link will help you understand the difference between chemical changes and physical changes, and how you can decide from observations you make. Click on the link and using the information on the left, complete the observation checklist for each event you select next to the screen.

http://www.glencoe.com/sites/common_assets/science/virtual_labs/E03/E03.html

This link has a video to help you understand chemical changes and a quiz you can take at the end:

http://studyjams.scholastic.com/studyjams/jams/science/matter/changes-of-matter.htm

Evaluation

See what you learned: this quiz will test your new knowledge of chemical changes.

Chemical Change Quiz

Choose which of the following are chemical changes. You can click on each one to check your answer.

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Burning wood Cutting paper Digesting food

Breaking glass Boiling water Fireworks exploding

Melting ice cream Freezing popsicles Frying an egg

Candle burning Water evaporating Lighting a match

Metal rusting An apple turning brown Baking a cake

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Conclusion

So what did you learn about chemical changes?

A chemical change is usually an irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance. The new substance formed in a chemical change or reaction differs in chemical properties and composition from the original substances. This can be shown by the following: