Sunday, January 30, 2011

Types of Reactions

Today we learned about the different kinds of chemical reactions that can occur. They are easily identifiable because each follows a specific pattern.

Synthesis:

A synthesis reaction is one in which two substances react to form a single substance.

Thus the equation A + B -------> AB

An example of a synthesis reaction is

__Ca + __CO3 -----> __CaCO3
As you can see, two substances combine to form one.
The balanced equation is

1 Ca + 1 CO3 ------> 1 CaCO3


Single Replacement

A single replacement reaction involves a compound and and element where atoms from the compound exchange places with the single element.

Thus the equation, AB + C = AC + B

An example of a single replacement reaction is
__NaCl + __I2 ------> __NaI + __Cl2

As you can see ,the iodine(non metal) traded places with the non metal in the NaCl equation, chlorine.

Balance : 2 NaCl  + 1 I2 -----> 2 NaI + 1 Cl2


Decomposition:

As the name implies, it is the breaking down of a substance into two different substances.

Therefore, the equation looks like

AB-----> A + B

An example of a decomposition reaction is

__KNO3 ---> ___KNO2 + __O2

The potassium nitrate breaks down into potassium nitrite and oxygen.

Balance! 2 KNO3 ------> 2 KNO2 + 1 O2

Here are some helpful links!
http://chemistry.about.com/library/formulabalance.pdf For extra practice!


A very visual demonstration http://www.youtube.com/watch?v=tE4668aarck

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