Balancing Chemical Reactions

By: Randomized & Aero1234

THE LAW CONSERVATION OF MASS

The Law Conservation of Mass states that mass cannot be created or destroyed.

The mass of the reactant is always equal to the product.

Mr. wildeboer’s notes!!

HOW TO BALANCE A CHEMICAL REACTION When you balance an equation you have to

have the same amount of atoms on both sides.

To do this you need to add coefficients in front of the element to make molecules. (You can’t change a subscript.)

Example: If you want to make 2 molecules of Aluminum then you have to add a coefficient not a subscript.

Al 2Al Al2

http://richardbowles.tripod.com/chemistry/balance.htm

EXAMPLE OF BALANCING CHEMICAL REACTIONS

H2+O2 H20

2 2 2 1 H2+O2 2H2O

2 2 4 2 2H2+02 2H2O

4 2 4

The Oxygen atoms combined with the Hydrogen atoms to form H20 but it is unbalanced.

Now we balanced the Oxygen atoms and we have to balance the Hydrogen atoms .

Now that there are 4 hydrogen atoms and 2 Oxygen atoms on both sides the chemical reaction is balanced.

Mr. Wildeboer’s notes http://www.webqc.org/balance.php

EXAMPLE 2

K+Br2 K+Br

1 2 1 1 2K+Br2 2K+Br

2 2 2 2

The Potassium atoms are already balanced now we have to balance the Bromine atoms.

Now every thing is balanced!

YAY!!!!!!!!!!Mr wildeboer’s notes

EXAMPLE 3

N2+H2 NH3

2 3 1 3

N2+H2 2NH3

2 2 2 6

N2+3H2 2NH3

2 6 2 6

The Hydrogen atoms are already balanced, but that will change. So we have to work on getting the Nitrogen atoms balanced.

We balanced the Nitrogen atoms but we un balanced the Hydrogen atoms. Now all we have to do is balance the Hydrogen atoms.

Now by adding 3 coefficient atoms to hydrogen and the multiplying that 3 times the 2 subscript you get 6 atoms on both sides for hydrogen and 2 atoms for Nitrogen. Everything is balanced now.

YAYYY AGAIN!!!!!!

EXAMPLES OF CHEMICAL EQUATIONS TO BALANCE

Fe + Cl2 = FeCl3 KMnO4 + HCl = KCl + MnCl2 + H2O + Cl2 K4Fe(CN)6 + H2SO4 + H2O = K2SO4 + FeSO4 + (NH4)2SO4

+ CO C6H5COOH + O2 = CO2 + H2O K4Fe(CN)6 + KMnO4 + H2SO4 = KHSO4 + Fe2(SO4)3 +

MnSO4 + HNO3 + CO2 + H2O Cr2O7{-2} + H{+} + {-} = Cr{+3} + H2O S{-2} + I2 = I{-} + S PhCH3 + KMnO4 + H2SO4 = PhCOOH + K2SO4 + MnSO4 +

H2O CuSO4*5H2O = CuSO4 + H2O

http://www.webqc.org/balance.php

BIBLIOGRAPHY

http://richardbowles.tripod.com/chemistry/balance.htm

http://chemistry.about.com/cs/stoichiometry/a/aa042903a.htm

http://www.webqc.org/balance.php http://

www.sky-web.net/science/balancing_chemical_equations.htm