The+difference+between+a+chemical+and+physical+reaction.+Part+2

What are the Differences between a Chemical and a Physical Reaction? Kiera T 2011 **Physical Reactions (Also known as a Physical Change)** A physical reaction takes place when two substances meet, and only the form changes, but not the composition. For example, when sugar and the water ar e mixed together, nothing new is created. The result is just water with sugar in it, the things that you started out with, therefore making it a physical reaction. Another example is when water freezes, then the ice melts, and then evaporates. The water is still water, just in different forms. Even when you crumple up a sheet of paper, you are causing a physical change. The composition of the paper is still the same, meaning the paper is still made up of the same things, the paper has just been crumpled into a different from.

A chemical reactions occurs when two or more substances meet, and they react in a way the either causes a change in the original substances, or the creations of one or two entirely new substances. A commonly known example is when vinegar and baking soda are mixed together. Vinegar is an acid, and baking soda is a base. When you mix them together, the baking soda releases OH-, (what makes something a base), and the vinegar releases H+, (what makes something an acid). Together, they create water and carbon dioxide, which was not part of t he original mixture, so it is a chemical reaction. Another example is when you soak a bone in vinegar. The bone has calcium in it, which is what makes it hard. Over time, the acid in the vinegar draws the calcium out of the bone, making the bone soft and
 * Chemical Reactions ( **** Also known as a Chemical Change) **

squishy. As a result, a change has taken place within the

bone, (the calcium has been removed), and also in the vinegar, (the extracted calcium has dissolved in it), making it a chemical reaction.

Resources: - Horton, Patricia et al. “ Physical and Chemical Changes” //The Nature of Matter.// New York: Glencoe Science, 2002. Print.

- Zeman, Anne and Kelly, Kate. //Everything You Need to Know About Science Homework.// New York: Scholastic Inc, 1997. Print. - [] September 13, 2011 Encyclopedia Britannica - Jasmine Tang (my mom) September 15, 2011

Glossary:
 * Acid** – A substance with a sour taste
 * Carbon Dioxide –** A colorless, odorless gas found in the atmosphere. Formula: CO2
 * Extract –** To take out or remove
 * Composition –** The nature of something’s ingredients