Chemical Reactions Part I - Ahmad Kilani

 In this class, we learned about 3 types of chemical reactions. Synthesis, Decompostion, and Single Replacement. 


The first one is Synthesis. 

A synthesis reaction is when two or more simple compounds combine to form a more complicated one. These reactions come in the general form of:

A + B ---> AB

One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide:

8 Fe + S₈ ---> 8 FeS

The second reaction is Decomposition.

A decomposition reaction is the opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones. These reactions come in the general form:

 

AB ---> A + B

One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas:

2 H₂O ---> 2 H₂ + O₂

The last one (for now) is Single Replacement.

This is when one element trades places with another element in a compound. These reactions come in the general form of:

A + BC ---> AC + B

One example of a Single Resplacement reaction is when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas:

Mg + 2 H₂O ---> Mg(OH)₂ + H₂

We also learned  how to tell if a single-replacement reaction would actually take place or not depending on the reactivity of the metal/nonmetal that's being reacted with:

If the metal/nonmetal is less reactive then no reaction takes place.  for example;

Mg + Cu(NO3)2 ---> Mg(NO3)2 + Cu  

-  This equation DOES take place since Magnesium is more reactive than Copper

2KI + 1Cl2 --->  2KCl + 1I2

-  Same thing can be done with non-metals.  Single replacement of non-metals.