1. Balancing Equations

2. Formulas show chemistry at a standstill.
Equations show chemistry in action.

3. Equations show: the reactants which enter into a reaction. H2 + O2
the products which are formed by the reaction.
 H2O
the relative amounts of each substance used and each substance produced.
2H2 + O  H2O

4. Equations must be balanced because:
Atoms can be neither created nor destroyed in an ordinary chemical reaction, so there must be the same number of atoms on both sides of the equation.
(Law of Conservation of Mass)

5. Two important principles to remember:
Every chemical compound has a formula which cannot be altered.
A chemical reaction must account for every atom that is used.

6. What an equation DOES NOT show:
Whether a reaction actually occurs
Speed of the reaction

7. + Sample Equation  N2 + H2  NH3 These formulas cannot be altered!
Choose one type of atom to balance:
Nitrogen

8. There are 2 N’s on the left and only 1 N on the right.
How can we get 2 Nitrogens on the right?
Only by adding another NH3 + 
N H  NH3
The nitrogens are balanced, but now you have 6 hydrogens on the right side and only 2 on the left.

9. What can we do? + 
N H  NH3

10. Some things to remember about writing equations:
The diatomic elements when they stand alone are always written H2, N2, O2, F2, Cl2, Br2, I2
The sign, ----->, means "yields" and shows the direction of the action.
A small delta, (), above the arrow shows that heat has been added.

11. p. 266

12. These numbers are found in a chemical equation:
Subscripts
The small numbers to the lower right of chemical symbols. Subscripts represent the number of atoms of each element in the molecule. These are never changed when balancing an equation.
Coefficients
The large numbers in front of chemical formulas. Coefficients represent the number of molecules of the substance in the reaction. Use these to balance.

13. Before beginning to balance an equation, check each formula to see that it is correct.
NEVER change a formula during the balancing of an equation.
Balancing is done by placing coefficients in front of the formulas.

14. The order in which the following steps are performed is important.
While shortcuts are possible, following these steps in order is the best way to be sure you are correct.

15. Balancing Equations By Inspection
There is a particular order that you can follow in balancing.
It is the MINOH method.
(Me know chemistry, said Tarzan as he climbed the stoichiome-tree.)

16. Balance metals such as Fe or Na first.
M - metals
Balance metals such as Fe or Na first.

17. I - ions
Looks for polyatomic ions (such as PO4¯ 3 or SO4¯ 2) that cross from reactant to product unchanged.
Balance them as a group.

18. Look for Cl or S, these are common ones.
N - non-metals
Look for Cl or S, these are common ones.

19. O – oxygen and H - hydrogen
Sometimes balancing H and O will involve water on one side or the other.
Often, either H or O will be spread out over several compounds. This is the one to leave to the last.
MINOH

20. Practice!!