1. Do Now – 3/4/10 Balance the following equation: Balance the following equation: __H 2 + __O 2  __H 2 O Get your homework out so I can check it while I am checking the Do Nows Get your homework out so I can check it while I am checking the Do Nows Setup Cornell Notes: “Balancing Equations” Setup Cornell Notes: “Balancing Equations” 21 2

2. Today 3/4/10 Do Now/Check HW Do Now/Check HW Cornell Notes – Balancing Equations Cornell Notes – Balancing Equations Practice Balancing Equations Practice Balancing Equations Work on Folders Work on Folders

3. Balancing Equations

4. Objectives By the end of the period, you should be able to... Demonstrate a comprehension of what a chemical equation is, in relating equations to food recipes Demonstrate a comprehension of what a chemical equation is, in relating equations to food recipes Describe the difference between Reactants and Products Describe the difference between Reactants and Products Balance equations on your own Balance equations on your own

5. How are these similar, how are they different? __ P4 + __ O2  __ P2O5 4 cups of Corn meal + 1 cup vegatable oil + 1 teaspoon flavoring  Flaming hot cheetos Write the above and your answer to the right, be prepared to share your responses (2 minutes) 2 similarities, 2 differnces NO TALKING YET!!

6. 2 SIDES to EQUATIONS Reactants On the left side The things that REACT!! Examples: 2H2 + O2 2 cups flour + 1 tsp salt + water Products On the Right side The finished product Examples: 2H2O Pizza Dough   

7. Why do equations need to be balanced? Law of Conservation of Matter: Law of Conservation of Matter: matter can be neither created nor destroyed. matter can be neither created nor destroyed. Reactants MUST = Products Reactants MUST = Products Can’t create something out of nothing Can’t create something out of nothing

8. Balancing Equations: Rules 1.The number of atoms of each type of element must be the same on each side of an equation. - 2 Hydrogens on left side, 2 Hydrogens on right

9. Balancing Equations: Rules 2. You can change the large number in front of each molecule (Coeficient), but not the small number 2H 2 + O 2 2 H 2 O 2H 2 + O 2 2 H 2 O

10. Balancing Equations: Rules 3. The large number infront, must be distributed to whatever it is infront of 2 H 2 O 2 H 2 O H = 4 O = 2

11. Balancing Equations: Rules 4. Reduce to lowest terms 2 N2 +6 H2  4 NH3 These can be divided by 2, so... 2/2=1, 6/2=3, 4/2=2 1 N2 +3 H2  2 NH3

12. Balancing Equations: Tips 1. Always balance Oxygen and Hydrogen last (think santa: ho ho ho) 2. If you get stuck... 1. Put a 1 infront of the most intimdating looking molcule and attempt to balance. 2. If that doesn’t work, put a 2 in front, etc.

13. How to balance Full Proof Method Full Proof Method 1. Brackets-list what you have If its by itself, gets own bracket If its by itself, gets own bracket 2. Multiply 3. Count ‘em 4. Check your work 5. Write in your large numbers (Coefficients) Short cut Don’t worry about this yet

14. Complete the Following on your Own 1. __Fe + __H 2 S0 4  __ Fe 2 (SO 4 ) 3 + __H 2 1. __Fe + __H 2 S0 4  __ Fe 2 (SO 4 ) 3 + __H 2 2. __C 2 H 6 + __O 2  __ H 2 O + __CO 2 2. __C 2 H 6 + __O 2  __ H 2 O + __CO 2 3. __KOH + __H 3 PO 4  __ K 3 PO 4 + __H 2 O 3. __KOH + __H 3 PO 4  __ K 3 PO 4 + __H 2 O 4. __SnO 2 + __H 2  __ Sn + __H 2 O 4. __SnO 2 + __H 2  __ Sn + __H 2 O 5. __NH 3 + __O 2  __ NO + __H 2 O 5. __NH 3 + __O 2  __ NO + __H 2 O

15. Folders: See example See example Front of folder: Cover page Front of folder: Cover page Title: Chapter 9: Title: Chapter 9:

16. Balancing Equations Hydrogen and oxygen are diatomic elements – they don’t like to be alone. Their subscripts cannot be changed. The subscripts on water cannot be changed. Hydrogen + oxygen water Hydrogen + oxygen water H 2 + O 2 H 2 O H 2 + O 2 H 2 O

17. Balancing Equation Count the atoms on each side. Reactant side: 2 atoms H and 2 atoms O Product side: 2 atoms H and 1 atom O H 2 + O 2 H 2 O H 2 + O 2 H 2 O

18. Balancing Equations H 2 + O 2 H 2 O H 2 + O 2 H 2 O If the subscripts cannot be altered, how can the atoms be made equal? If the subscripts cannot be altered, how can the atoms be made equal? Adjust the number of molecules by changing the coefficients. Adjust the number of molecules by changing the coefficients.

19. Balancing Equations Reactants: 2 atoms of H and 2 atoms of O Products: 4 atoms of H and 2 atoms of O H is no longer balanced! H 2 + O 2 2H 2 O H 2 + O 2 2H 2 O

20. Balancing Equations Reactant side: 4 atoms of H and 2 atoms of O Product side: 4 atoms of H and 2 atoms of O It’s Balanced! 2H 2 + O 2 2H 2 O 2H 2 + O 2 2H 2 O

21. Balancing Equations Count atoms. Reactants: 2 atoms N and 2 atoms H Products: 1 atom N and 3 atoms of NH 3 N 2 + H 2 NH 3 N 2 + H 2 NH 3 Nitrogen + hydrogen ammonia Nitrogen + hydrogen ammonia

22. Balancing Equations Nothing is balanced. Nothing is balanced. Balance the nitrogen first by placing a coefficient of 2 in front of the NH 3. Balance the nitrogen first by placing a coefficient of 2 in front of the NH 3. N 2 + H 2 2NH 3 N 2 + H 2 2NH 3

23. Balancing Equations Hydrogen is not balanced. Hydrogen is not balanced. Place a 3 in front of H 2. Place a 3 in front of H 2. Reactant side: 2 atoms N, 6 atoms H Reactant side: 2 atoms N, 6 atoms H Product side: 2 atoms N, 6 atoms H Product side: 2 atoms N, 6 atoms H N 2 + 3H 2 2NH 3 N 2 + 3H 2 2NH 3

24. Balancing Equations Count atoms. Reactants: Ca – 3 atoms, P – 2 atoms, O – 8 atoms; H – atoms, S – 1 atom, O – 4 atoms Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4 Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4

25. Balancing Equations Side note on Ca 3 (PO 4 ) 2 Side note on Ca 3 (PO 4 ) 2 The subscript after the phosphate indicates two phosphate groups. The subscript after the phosphate indicates two phosphate groups. This means two PO 4 3- groups with two P and eight O atoms. This means two PO 4 3- groups with two P and eight O atoms.

26. Balancing Equations Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4 Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4 Count atoms in the product. Ca atoms – 1, S atom – 1, O atoms – 4; H atoms – 3, P atom – 1, O atoms - 4

27. Balancing Equations In this equation, the ion groups do not break up. In this equation, the ion groups do not break up. Instead of counting individual atoms, ion groups may be counted. Instead of counting individual atoms, ion groups may be counted. Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4

28. Balancing Equations Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4 Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4 Reactants: Ca 2+ – 3, PO 4 3- - 2, H + – 2, SO 4 2+ - 1 Products: Ca 2+ - 1, SO 4 2- - 1, H + - 3, PO 4 3- - 1

29. Balancing Equations Balance the metal first by placing a coefficient of 3 in front of CaSO 4. Balance the metal first by placing a coefficient of 3 in front of CaSO 4. Products: Ca – 3 atoms, SO 4 2- - 3 groups Products: Ca – 3 atoms, SO 4 2- - 3 groups Ca 3 (PO 4 ) 2 + H 2 SO 4 3CaSO 4 + H 3 PO 4

30. Balancing Equations Three sulfate groups are needed on the reactant side so place a coefficient of 3 in front of H 2 SO 4. Three sulfate groups are needed on the reactant side so place a coefficient of 3 in front of H 2 SO 4. 3H 2 SO 4 gives 6 H + and 3 SO 4 2-. 3H 2 SO 4 gives 6 H + and 3 SO 4 2-. Neither phosphate nor calcium is balanced. Neither phosphate nor calcium is balanced. Ca 3 (PO 4 ) 2 + 3H 2 SO 4 3CaSO 4 + H 3 PO 4

31. Balancing Equations A coefficient of 2 placed in front of H 3 PO 4 which balances both hydrogen and phosphate. A coefficient of 2 placed in front of H 3 PO 4 which balances both hydrogen and phosphate. Ca 3 (PO 4 ) 2 + 3H 2 SO 4 3CaSO 4 + 2H 3 PO 4

32. Balancing Equations The sulfate group breaks up. Each atom must be counted individually. Ugh! Reactants: Cu – 1, H – 2, S – 1, O – 4 Products: Cu – 1, S – 1, O - 4, H – 2, O – 1, S – 1, O - 2 Cu + H 2 SO 4 Cu + H 2 SO 4 CuSO 4 + H 2 O + SO 2 CuSO 4 + H 2 O + SO 2

33. Balancing Equations Sulfur is not balanced. Sulfur is not balanced. Place a two in front of sulfuric acid. Place a two in front of sulfuric acid. Count atoms: 2 H 2 SO 4 H – 4, S – 2, O - 8 Count atoms: 2 H 2 SO 4 H – 4, S – 2, O - 8 Cu + 2H 2 SO 4 CuSO 4 + H 2 O + SO 2

34. Balancing Equations Hydrogen needs to be balanced so place a 2 in front of the H 2 O. Hydrogen needs to be balanced so place a 2 in front of the H 2 O. Count the number of atoms. Count the number of atoms. Cu + 2H 2 SO 4 CuSO 4 + 2H 2 O + SO 2

35. Balancing Equations Reactants: Cu – 1, H – 4, S – 2, O – 8 Reactants: Cu – 1, H – 4, S – 2, O – 8 Products: Cu – 1, S – 1, O – 4, H – 4, O – 2, S – 1, O – 2 = Cu – 1, S – 2, H – 4, O – 8 Products: Cu – 1, S – 1, O – 4, H – 4, O – 2, S – 1, O – 2 = Cu – 1, S – 2, H – 4, O – 8 It’s balanced! It’s balanced! Cu + 2H 2 SO 4 CuSO 4 + 2H 2 O + SO 2

36. Balancing Equations Balancing hints: Balancing hints: Balance the metals first. Balance the metals first. Balance the ion groups next. Balance the ion groups next. Balance the other atoms. Balance the other atoms. Save the non ion group oxygen and hydrogen until the end. Save the non ion group oxygen and hydrogen until the end.

37. Balancing Equations This method of balancing equations is the inspection method. This method of balancing equations is the inspection method. The method is trial and error. The method is trial and error. Practice. Practice.

38. Writing and Naming Write the corresponding formula equation and then balance the equation. Nickel + hydrochloric acid Nickel + hydrochloric acid Nickel(II) chloride + hydrogen Nickel(II) chloride + hydrogen

39. Writing and Naming Write each formula independently. Write each formula independently. Ignore the rest of the equation. Ignore the rest of the equation. Balance the equation after writing the formulas. Balance the equation after writing the formulas. Ni + HCl NiCl 2 + H 2 Ni + HCl NiCl 2 + H 2 Ni + 2HCl NiCl 2 + H 2 Ni + 2HCl NiCl 2 + H 2

40. Writing and Naming Remember the diatomic elements: H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2. Remember the diatomic elements: H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2.

41. Writing and Naming Balance the formula equation. Write the word equation. Cu + H 2 SO 4 Cu + H 2 SO 4 CuSO 4 + H 2 O + SO 2 CuSO 4 + H 2 O + SO 2

42. Writing and Naming Cu + 2H 2 SO 4 Cu + 2H 2 SO 4 CuSO 4 + 2H 2 O + SO 2 CuSO 4 + 2H 2 O + SO 2 Write the names: Cu by itself is just copper. Copper(I) or copper(II) would be incorrect. H 2 SO 4 should be named as an acid. Sulfuric acid

43. Writing and Naming CuSO 4 has a SO 4 2- group so Cu must be 2+. Some metals must have Roman Numerals. Copper(II) sulfate CuSO 4 has a SO 4 2- group so Cu must be 2+. Some metals must have Roman Numerals. Copper(II) sulfate H 2 O is known as water. H 2 O is known as water. SO 2 is a nonmetal compound. Its name is either sulfur dioxide or sulfur(IV) oxide. SO 2 is a nonmetal compound. Its name is either sulfur dioxide or sulfur(IV) oxide.

44. Writing and Naming Copper + sulfuric acid  Copper(II) sulfate + water + sulfur dioxide Cu + 2H 2 SO 4 Cu + 2H 2 SO 4 CuSO 4 + 2H 2 O + SO 2 CuSO 4 + 2H 2 O + SO 2