Sunday, January 30, 2011

Types of Reactions

Remember the 6 different types of reactions we learned when we were in grade 9, 10?
Synthesis, Decomposistion, Single Replacement, Double Replacement, Combustion and Neautralization? Don't worry if you forgot we're gonna review them today!

Synthesis:
      The combination of two or more substances to form a compound
              ex. C + O2 ------>  CO2
              ex. H2 +Cl2 -----> 2HCl
     General Form: A+B----> C


Decomposition:
       Is a reaction being able to break down a molecule into a simpler substance
             ex. 2AgO + heat ----> 4Ag + O2
             ex. 2NO+ heat-----> N2 + O2
     General Formula: AB----> A+B


Single Replacement:
       A reaction involves replacing one atom in a compound by another atom.
             ex. Cu2Cl2 + Fe---> FeCl2 + Cu
             ex. Cl2 + 2KI---> I2 + 2KCL
       General Formula: A+BC---> B+AC


How to predict Single Replacements:

- If the reacting element is a metal then trade places with the metal atom in the compound
- If the reacting element is non-metal then trade places with the non-metal atom in the compound 
Use the Activity Reaction Chart linked below...
Activity Series Chart Link

Lets use an example of a metal : CuI2  + Fe

Remember that the metal switches with the metal, so the Copper (Cu) must switch places with Iron (Fe).
It should look something like this CuI2 + Fe ----> FeI2 + Cu

Let's use anther example of a non-metal: CuI2 + Br2

Remember that the non-metal switches with the non-metal, so Iodine (I) switches with Bromine (Br).
It should look like this CuI2 + Br2 ----> BuBr2 + I2




PRACTICE TIME!!!

1) Cl2 + CaBr2 --->
2) Mg + ZnSO4 --->
3) Al + O2 --->
4) ICl --->
5) Zn +S8 --->
6) Zn + Ni(NO3)2 --->
7) NH3 --->
8) Cl2 + KI --->
9) 3Mg + 2AlCl3 --->
10) 2CrBr3 + 3Zn --->



Answers:
1) Cl2 + CaBr2 ---> Br2 + CaCl2
2) Mg + ZnSO4 ---> Zn + MgSO4
3) 4Al + 3O2 ---> 2Al2O3
4) 2ICl ---> I2 +Cl2
5) 8Zn +S8 ---> 8ZnS
6) Zn + Ni(NO3)2 ---> Ni +Zn(NO3)2
7) 2NH3 ---> N2 +3H2
8) Cl2 + 2KI ---> 2KCl +I2
9) 3Mg + 2AlCl3 ---> 3MgCl2 + 2Al
10) 2CrBr3 + 3Zn ---> 3ZnBr2 + 2Cr

More practices use these links:


Answers to the practices


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