2. Chemical Reaction A process in which one or more substances are converted into new substances with different physical and chemical properties

3. Chemical Equations Reactants – the elements and/or compounds on the LEFT side of the equation Products – the elements and/or compounds on the RIGHT side of the equation  means “yields” or “produces”

4. Two way to write equations: 1. Word Equations Ex: magnesium reacts with sulfur to produce magnesium sulfide 2. Formula Equations Ex: Mg + S  MgS

5. Write the formula equation for the following word equation: Oxygen reacts with sodium fluoride to produce sodium oxide and fluorine O 2 + NaF  Na 2 O + F 2

6. Your turn 1.Hydrogen plus oxygen yields water 2.Aluminum bromide plus chlorine yields aluminum chloride and bromine 3.Iron plus lead(II) sulfate react forming iron(II) sulfate plus lead 4.Potassium chlorate when heated produces potassium chloride plus oxygen

7. 1.H 2 + O 2 → H 2 O 2.AlBr 3 + Cl 2 → AlCl 3 + Br 2 3.Fe + PbSO 4 → FeSO 4 + Pb 4.KClO 3 → KCl + O 2

8. Balancing Equations

9. Law of Conservation of Matter States that matter is not created or destroyed Mass of Reactants = Mass of Products

10. Balancing Equations You must make sure there are the SAME NUMBER of each element on both sides of the equation Ex: Na + Br 2  NaBr 2Na + Br 2  2NaBr Coefficients- the numbers used to balance an equation that specify the amount of elements or compounds used in the reaction.

11. A B C DE Subscripts mean number of atoms bonded together Reactants Products Yields Subscripts Coefficient Coefficient means the number of the elements or compounds. It’s a multiplier

12. C2H6C2H6 How many atoms are represented C = ________H = _________ 2Na 2 SO 4 How many atoms are represented Na = ________S = _________ O = _________

13. How to balance chemical reaction Atom inventory of reactants and products Balance atoms one element at a time Verify your results (double check) HINTS: 1. Balance elements that appear once first

14. 2. Balance Hydrogen and oxygen last 3. Odd-even technique (even # of atom on one side and odd # of the same atom on other) Multiplying an odd number by 2 will result in an even number ***practice, practice, practice***

15. H = 2 Cl = 2 H = 1 Cl =1 2 2

16. Be = 1 O = 2 Be =1 O = 1 2 2 2

17. Ca + 2H 2 O  Ca(OH) 2 + H 2 Ca = 1 H = 2 O = 1 Ca = 1 H = 4 O = 2 4 2

18. N 2 + 3H 2  2NH 3 N = 2 H = 2 N = 1 H = 3 2 6 6

19. Balance the following chemical equations 1. _____ H 2 + _____ O 2 -------> _____ H 2 O 2.___KClO 3 ---> ___KCl + ___ O 2 3. _____ N 2 + _____ O 2 -------> _____ N 2 O 4. _____ HgO -------> _____ Hg + _____ O 2

20. Balance the following chemical equations 1._____ P 4 + _____ O 2 ------------> ____ P 2 O 5 2._____ K + _____ Br 2 ----------> ____ KBr 3._____ Na + ____ H 2 O -------> ____ NaOH + ____ H 2 4._____ S 8 + _____ O 2 -------> _____ SO 3