1. Balancing Chemical Equations By: Alexander K., Andrew R. and David M.

2. Parts of an equation

3. The Basics 1. Figure out the correct formulas for all reactants and products. 2. Write the formulas for the reactants on the left and the formulas for the products on the right with a yields sign(  ) in between. If two or more reactants or products are in the equation, separate their formulas with plus signs. 3. Count the number of atoms of each element in the reactants and products. For simplicity, a polyatomic ion appearing uncharged on both sides of the equation is counted as a single unit. 4. Balance the elements one at a time by using coefficients (Coefficient is a small whole number that appears in front of a chemical formula in an equation). When no coefficient is written, it is assumed to be 1. It is best to begin the balancing operation with elements that appear only once on each side of the equation.( Do not attempt to balance equation by changing the subscripts in the chemical formula of a substance) 5. Check each atom or polyatomic ion to be sure that the equation is balanced. 6. Finally, make sure that all the coefficients are in the lowest possible ratio.

4. How to Balance Equations

5. How to Balance Combustion Equations The only form of a combustion equation is hydrocarbon molecule reacting with oxygen to produce carbon dioxide and water as a result. Balance the carbon and hydrogen first and then proceed accordingly

6. Combustion Equation

7. Practice chemical equations 1) __PbO2  __PbO +__O2 A) 4PbO2  4PbO + O2 B) PbO2  2PbO + O2 C) 2PbO2  2PbO + O2 D) 12PbO2  8PbO + 6O2 The correct answer is C.

8. Practice chemical equation 1) __NaNO3 + __PbO  __Pb(NO3)2 + __Na2O A) 2NaNO3 + PbO  Pb(NO3)2 + Na2O B) 3NaNO3 + 4PbO  7Pb(NO3)2 + 2Na2O C) 4NaNO3 + 2PbO  2Pb(NO3)2 + 2Na2O D) 2NaNO3 + 4PbO  3Pb(NO3)2 + Na2O The correct answer is A

9. PQP (A.K.A. your homework) Balance the following equations: a. P + O2  P4O10 b. Fe + Cl2  FeCl3 Balance the following combustion equations: a.C 5 H12 + O2  CO2 + H2O b. C2H5OH + O2  CO2 +H2O

10. THE END