1. Balancing Equations

2. Balancing Equations

3. Balancing Equations Law of Conservation of Matter:
In a chemical reaction, matter can be neither created nor destroyed.
In a chemical reaction, the amount of reactants equal the amount of products.

4. Balancing Equations Paraphrased: Law of Conservation of Atoms:
The number of atoms of each type of element must be the same on each side of the equation.

5. Chemical Equations

6. Balancing Chemical Equations
Draw a reactant/ product table, listing each atom type.
Count each atom on both sides of equation.
Balance by trial & error (one atom at a time) until you have the same # of atoms of each element on both sides of the equation.
Balance by adding coefficients, not subscripts.
Zn(s) + _HCl(aq)  ZnCl2(aq) + H2(g) R P Zn 1 H 2 Cl

7. Hydrogen + oxygen water
Balancing Equations
Hydrogen + oxygen water
H2 + O H2O

8. Nitrogen + hydrogen ammonia
Balancing Equations
N2 + H NH3
Nitrogen + hydrogen ammonia

9. Balancing Equations
Ca3(PO4)2 + H2SO4 CaSO4 + H3PO4

10. Balancing Equations
Cu + H2SO4
CuSO H2O + SO2

11. NaOH + CaBr2  Ca(OH)2 + NaBr

12. C2H6 + O2  CO2 + H2O

13. Key to Balancing Equations
Practice!
Trial & Error!!!

14. Balancing chemical equations
_ Na + _Cl2 → _ NaCl
_ Fe(s) + _ Cl2(g) → _ FeCl3
_ Ag2O → _ Ag + _O2
4. _ CuCl _ Al → _ AlCl3 + _ Cu
5. _ AgNO3 + _MgCl2 → _ AgCl + _Mg(NO3)2

15. Types of Chemical Rxns Classifying reactions
There are 5 general types of reactions
Combustion
Synthesis (Combination)
Decomposition
Single-replacement (single-displacement)
Double-replacement (double-displacement)
Not all chemical reactions fit uniquely into only one of these classes
Sometimes, one rxn may fit 2 or 3 different types