Home Page Matter Atoms Elements Reactions Biochemistry Activities Chem4kids Sections Search
Chemical Reactions

Chemical Reactions

Reactions involve the chemical change of atoms and molecules.

Let's start with the idea of a chemical reaction. Reactions occur when two or more molecules interact and the molecules change. Bonds between atoms are broken and created to form new molecules. That's it. What molecules are they? How do they interact? What happens? The possibilities are infinite.

When you are trying to understand chemical reactions, imagine that you are working with the atoms. Imagine the building blocks are right in front of you on the table. Sometimes we use our chemistry toys to help us visualize the movement of the atoms. We plug and unplug the little connectors that represent chemical bonds. There are a few key points you should know about chemical reactions:

1. A chemical change must occur. You start with one molecule and turn it into another. Chemical bonds are made or broken in order to create a new molecule. One example of a chemical reaction is the rusting of a steel garbage can. That rusting happens because the iron (Fe) in the metal combines with oxygen (O2) in the atmosphere. Chemical bonds are created and destroyed to finally make iron oxide (Fe2O3).

Hydrogen and oxygen molecules combine to form water in a synthesis reaction. When a refrigerator or air conditioner cools the air, there is no reaction in the air molecules. The change in temperature is a physical change. When you melt an ice cube, it is a physical change. When you put bleach in the washing machine to clean your clothes, a chemical change breaks up the molecules in your stains.

2. A reaction could include atoms, ions, compounds, or molecules of a single element. You need to remember that a chemical reaction can happen with anything, just as long as a chemical change occurs. If you put pure hydrogen gas (H2) and pure oxygen gas in a room, they might be involved in a reaction to form water (H2O). However, it will be in very very small amounts. If you were to add a spark, those gases would be involved in a violent chemical reaction that would result in a huge explosion (exothermic). Another chemical reaction might include silver ions (Ag+). If you mix a solution with silver ions with a solution that has chloride (Cl-) ions, silver chloride (AgCl) precipitate will form and drop out of solution.

Series of Chemical Reactions 3. Single reactions often happen as part of a larger series of reactions. When a plant makes sugars, there might be as many as a dozen chemical reactions to get through the Calvin cycle and eventually create (synthesize) glucose (C6H12O6) molecules. The rusting example we used earlier only showed you the original reactants and final products of the chemical reaction. There were several intermediate reactions where chemical bonds were created and destroyed. The silver chloride example only focused on the ions. In reality, the two solutions were created when two salts dissociated (split into ions) in water.

Related Activities

Chemistry Quiz Reactions Quiz Next Stop On Chem4Kids Tour
Next Page on Reactions

Mars: Why is Curiosity Looking for Organics? (NASA/JPL Video)

- Chem4Kids: Rates of Reactions
- Biology4Kids: Photosynthesis
- Biology4Kids: Homeostasis
- Geography4Kids: BGC Cycles
- Geography4Kids: Food Webs
- Geography4Kids: Temperatures
- Physics4Kids: Thermodynamics
- Physics4Kids: Thermo Laws
> Overview
- Rates
- Measuring
- Stoichiometry
- Thermodynamics
- Equilibrium I
- Equilibrium II
- Catalysts and Inhibitors
- Acids/Bases I
- Acids/Bases II


Link to Link to Link to Link to Link to Link to Rader Network Side Navigation


Useful Reference Materials
Encyclopædia Britannica:
Rhode Island College:
Books on
- Prentice Hall Chemistry (Wilbraham)
- Chemistry (McMurry)
- Chemistry: The Molecular Nature of Matter and Change (Silberberg)
- Books About Chemical Reactions
- Chemical Reaction Engineering (Levenspiel)


Help Page Go for site help or a list of chemistry topics at the site map!
©copyright 1997-2015 Andrew Rader Studios, All rights reserved.
Current Page: | Reactions | Overview

** Andrew Rader Studios does not monitor or review the content available at external web sites. They are paid advertisements and neither partners nor recommended web sites. Specific links for books on are only suggested starting points for further research. Please browse, research options, and choose the appropriate materials for your needs.