Types of Reaction and Balancing Equation

Balancing Equations

The number of atoms the reactant side = the product side.

1.      Balance the atoms only occur in one molecule on each side of equation

2.      Don’t considering atoms separately, Balance whole groups whenever possible

3.       Don’t jump all over an equation, balancing a bit here and a bit there. Be systematic

4.      Balance atoms which occur in elemental form last. By elemental form we mean that the atoms are not combined with any atoms of a different kind

Li+ MgCl2 -> LiCl +Mg

Balance: 2Li+ MgCl2 -> 2LiCl +Mg

An equation isn’t properly balanced until we have actually balance both side

Ionic Compounds

Na SO4   Sodium Sulphate

K2Cl   Potassium Chloride

Fe2S3   Iron (III) Sulphide

Covalent Compound

1= mono, 7= hepta

2= di    8= octa

3= tri    9= nona

4= tetra  10= deca

5= penta 11= hendeca

6= hexa  12= dodeca

Acids

HCl= Hydro Chloric acid

H2SO4= Sulphurous acid

Types of Reactions

1.      Synthesis

It’s a reaction that combines 2 or more reactants to from one product

X+Y -> Z

Na+Cl-> NaCl

2.      Decomposition

It’s a reaction that breaks down one reactant in to 2 or more products

XY-> X+Y

NaCl-> Na+Cl

3.      Single replacement

It’s one where an element replaces an ion in a ionic compound. Metal replace positive ions (cations) and non metal replace negative ions (anions)

X+YZ-> XZ+Y (X= metal)

X+YZ-> ZY+Z (X= non mental)

2Al+ 3CuCl2-> 2AlCl3+ 3Cu

Predicting Single replacement reactions

Some metals are more reactive than other metals. So the metal has to be higher than the replace one to have reactions. Apply to both metals and non metal

Fe+ ZnCl2-> NR (because Fe isn’t more reactive than Zn)

3Mg+ 2AlCl3-> 3MgCl2+ 2Al (Yes because Mg is more reactive than Al)

4. Double replacement

A double replacement is a reaction between 2 ionic compounds usually in solution

WX+YZ-> WZ+XY

K2CO3+BaCl2-> 2KCl+ BaCO3

If the reactants change start during the reaction, this is a reaction occurring (usually precipitate forming)

If there’s no change of state, then there’s no reaction

Use “Table of Solubilities” to determine the states –(aq) or (s)

5. Combustion

It’s a reaction where burning in air is involved. The reactants are the chemical to be burned and the oxygen that it reacts with. The oxygen usually ends up combine more than one type of atoms as products.

AB+O2-> AO+BO

C4H8+6O2-> 4CO2+H2O

6. Neutralization

It’s a special double replacement reaction where acid react with bases to produce water

The acids have an H (+) as the cation and the bases have OH as the anion (-). Both should be (aq)

HA+BOH-> H2O+BA

        2HBr+Sr (OH) 2-> SrBr2+ 2H2O