Feb 4th - Nick Kim

Today we revised, how to do double replacement, Net ionic equations, and combustion
First, double replacement is a reaction between two ionic compounds. The positive ions switch their partners(negative ions) each others and form new ionic compounds. After balance the equations by writing numbers in front of forumla so that number of particles are same
Ex, 2Na3PO4(aq)+3Ca(NO3)2(aq)---6NaNO3(aq)+Ca3(PO4)2(s)
When double replacement is done, we use Net ionic equation if it is possible. We cancel out the same elements on each side, but they should have same number of particles and need to be (aq)

Ex,2Na3PO4(aq)+3Ca(NO3)2(aq)---6NaNO3(aq)+Ca3(PO4)2(s) example above
Na cancel each other since they have same number of particles and (aq)
Po4 won't cancel each other because right side is (s)
NO3 will work too because they both have same number of particles and (aq)
Therefore, new equation is 3Ca+2PO4---Ca3(PO4)2

Combustion is a reaction that involve burning in air.
General Formula:
AB+O2---AO+BO
Ex,
C4H8+6O2---4CO2+4H2O

Practice Questions(double replacement)
http://chemwiki.wikidot.com/double-replacement-reaction-problems

Practice Questions(Net ionic equation)
http://www.ccsf.edu/Departments/Chemistry/chem101a/resourc/net_ion2.htm

Videos that will help
http://www.youtube.com/watch?v=y-xLlY18_Mk
http://www.youtube.com/watch?v=I2liasSXCXM
http://www.youtube.com/watch?v=CqftRowoNKY