1. Chapter 6

2. Counting Atoms Subscripts indicate the number of atoms in a COMPOUND

3. Example H 2 O 2 Hydrogen Atoms 1 Oxygen The number 1 is INVISIBLE

4. H 2 O Coefficient Subscript

5. Number of Number of Molecules Atoms H2OH2O

6. MULTIPLY Coefficient x Subscript 2 Ag 1 Cl 2

7. Molecules: Two Atoms 2x1 = 2 Ag Atoms 2x2= 4 Cl Atoms 2 AgCl 2

8. 4 NaCl Molecules = 4 Atoms: 4 Sodium Atoms 4 Chlorine Atoms

9. 2 Ca(OH) 2 Molecules = 2 Atoms: 2 Calcium Atoms 4 Oxygen Atoms 4 Hydrogen

10. 3 H 2 O Molecules = 3 Atoms: 6 Hydrogen Atoms 3 Oxygen Atoms

11. 4 CO 2 Molecules = 4 Atoms: 4 Carbon Atoms 8 Oxygen Atoms

13. An expression that uses chemical formulas and symbols to describe a reaction

14. Chemical Equation R + R P + P R = Reactant P= Product

15. Reactants Start the reaction At the Beginning LEFT SIDE OF ARROW

16. “ARROW” Yields

17. Products New substance(s) Product = Finished RIGHT OF THE ARROW

18. Identify Products and Reactants

19. Reactants Products

20. Na + Cl 2 NaCl Mg + O 2 MgO

21. Al 2 O 3 Al + O 2 KCl + F 2 KF + Cl 2

23. To obey the Law of Conservation of Mass

24. Atoms CANNOT be created or destroyed Mass of reactants = Mass of products

25. Fe + S FeS 14 g + 8 g 22 g 22 g = 22 g Mass of REACTANTS Mass of PRODUCTS

26. Ca + Cl 2 CaCl 2 6 g + _?_ g 12 g 6 + ? g = 12 g 6 g

27. Fe + S FeS ? g + 16.0g 44.0 g ? + 16.0 g = 44.0 g 28.0 g

28. 1 Ca 2Cl 1Ca 2Cl Ca + Cl 2 CaCl 2 Balanced

29. Sn + Cl 2 SnCl 2 1Sn 2Cl Balanced

30. 1Na 2F 1Na 1F Na + F 2 NaF Not Balanced 2Na + F 2 2NaF 2X1=2 2X1 =2 (Na) 2X1 = 2 (F)

31. Balancing Chemical Equations Step 1: Write the equation

32. Step 2: Count the Atoms

33. Step 3: Use COEFFICIENTS to Balance Atoms

34. H2OH2O Coefficient Subscript

35. Step 4: Double Check Math

37. _Ag + _S _Ag 2 S _Mg + _O 2 _MgO _H 2 + _N 2 _NH 3

38. 2Ag + _S _Ag 2 S 2Mg + _O 2 2MgO 3H 2 + _N 2 2NH 3

39. Classifying Chemical Reactions

40. 1. Synthesis To put together 2 reactants 1 product

41. Example: H 2 + O 2 H 2 O

42. 2. Decomposition To tear apart (breakdown) 1 reactant 2 products

43. Example H 2 O H 2 + O 2

44. 3. Single Replacement 2 reactants 2 products Look for a SINGLE element!

45. Example: Cu 2 O + C Cu + CO 2 Single Element Single Element

46. 4. Double Replacement 2 reactants 2 products Jackpot! Compound + Compound

47. Example: FeS +HCl FeCl 2 + H 2 S

48. H2OH2O Coefficient Subscript

49. Number of Number of Molecules Atoms H2OH2O

50. MULTIPLY Coefficient x Subscript 2 Ag 1 Cl 2

51. Molecules: Two Atoms 2x1 = 2 Ag Atoms 2x2= 4 Cl Atoms 2 AgCl 2

52. 4 NaCl Molecules = 4 Atoms: 4 Sodium Atoms 4 Chlorine Atoms

53. 3 H 2 O Molecules = 3 Atoms: 6 Hydrogen Atoms 3 Oxygen Atoms

54. 4 CO 2 Molecules = 4 Atoms: 4 Carbon Atoms 8 Oxygen Atoms

56. Indicators Compounds that change color when it contacts an acid or a base

57. Properties of Acids Sour taste Reacts with metals (corrosive) Turns litmus paper red

58. Properties of Bases Bitter Taste Slippery Feel Turns Litmus paper Blue

60. Acids Produce Hydrogen Ions (H + ) in water

61. Bases Produce Hydroxide ions (OH - ) in water

62. The pH scale

63. Range of numbers from 0-14 Indicates H + ions

64. The pH scale <7 ACID 7 Water >7 BASE