Chemical Reactions and more...

October 4, 2012

Hello everyone, today we learned about the 5 types of chemical reactions.  Those include: synthesis reactions, decomposition reactions, single replacement reactions,  and double replacement reactions.

A synthesis reaction is when two reactants form to make a product

so it would be like A (reactant) + B (reactant) --->  AB (product)

an example of this is  8 Fe + S₈ ---> 8  FeS     

<sub>This is because you have two reactants (Fe and S) when reacted become a product.  

Also, here is a video demonstrating a synthesis reaction, and someone screaming in the background:
http://www.youtube.com/watch?v=gHkyO7pMj0U&feature=plcp 

In addition, another reaction is decomposition reactions.
 A decomposition  it breaks down into its component elements or simpler compounds. The anion determines what the product will be.  
Here is another awesome video directed by me about decomposition:
 http://www.youtube.com/watch?v=Nr5EXzDq28g

For example, an example of a decomposition reaction is 
 2Cl2O5 → 2Cl2  + 5O2  

 It goes from from a compound (2Cl2O5) into smaller elements (2Cl2  + 5O2) and thus is a decomposition reaction.

3rdly, we get to single replacement reactions, which are when one element replaces another element in a compound.
for example; element + compound --> product + product 
remember that the biggest mistake is people forgetting the cation goes first.</sub> 

<sub>Here is a picture of Mr. Lieberman demonstrating a single replacement reaction: 

4thly, we went over double replacement reactions.  which are when a metal replaces another metal in a compound and a nonmetal does the same thing to another nonmetal.
an example of this is: HCl +NaOH --> NaCl +H2O because one metal replaces another and one nonmetal replaces another.

Finally, we get to combustion, which we didn't really have time to go over in class, and it less important than the 4 previous reactions.  Combustion reactions are when hydrocarbon reacts with oxygen gas, also called burning.  to make things burn, you need a fuel, oxygen, and a spark.  So any equation with just hydrocarbon and oxygen is a combustion equation.

Hw: Chemical reactions wksht, quiz on friday.  3.4 WA is up, so maybe get started on that sometime before 3 am the night before the test. 
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Scribe for next week:  Kevin L.</sub>