A chemical reaction happens when one or more chemicals are changed into one or more other chemicals. Examples:
- iron and oxygen combining to make rust
- vinegar and baking soda combining to make sodium acetate, carbon dioxide and water
- things burning or exploding
- many reactions that happen inside living things
Some reactions are very fast, and others are very slow. Some happen at different speeds, depending on temperature or other things. For example, wood does not react with air when it is cold, but if it is made hot enough, it will start to burn. Other reactions such as Nuclear Reactions differ in the way that Nuclear Reaction does not need a catalyst. They also cannot be stopped, sped up or slowed down.
Some reactions give out energy. These are called exothermic. In other reactions, energy is taken in. These are called endothermic.
Four basic types[change | change source]
Synthesis[change | change source]
In a synthesis reaction, two or more simple substances combine to form a more complex substance.
Another example is simple hydrogen gas combined with simple oxygen gas to produce a more complex substance, such as water.
Decomposition[change | change source]
Single replacement[change | change source]
In a single replacement reaction, a single uncombined element replaces another in a compound; in other words, one element trades places with another element in a compound These reactions come in the general form of:
Double replacement[change | change source]
Equations[change | change source]
A chemical reaction is being displayed by an equation:
- Here, A and B react to C and D in a chemical reaction.
- This is an example of a combustion reaction.
Related pages[change | change source]
Other websites[change | change source]
- Rates of reaction
- Online chemical equation balancer Balances equation of any chemical reaction (full or half-cell) in one click.