1. Periodic Table and Molar Masses

2. An isotope is an atom with a particular number of neutrons.
You identify an isotope with its symbol and its mass number
Mass number = protons + neutrons
Example C -14
C is the symbol and 14 is the mass number
C = carbon 14 = 6 protons neutrons

3. What is the isotope? Example Atomic number 27 and 32 neutrons
Answer Co - 59

4. Atomic number 74 and 110 neutrons

5. W - 184

6. Mass number 29 and 15 neutrons

7. Si - 29

8. 26 positive charges in the nucleus and 30 neutral charges in the nucleus

9. Fe - 56

10. Example Molar mass of H2O? Answer 2 Hydrogens + 1 Oxygen
What is the molar mass?
Example Molar mass of H2O?
Answer 2 Hydrogens + 1 Oxygen
= 18 grams/mole

11. CO2

12. CO2
44.0 grams/mole

13. NaOH

14. NaOH
40.0 grams/mole

15. KCl

16. KCl
74.0 grams/mole

17. C6H12O6

18. C6H12O6
180.0 grams/mole

19. MgCl2

20. MgCl2
95.2 grams/mole

21. CrO7

22. CrO7
164.0 grams/mole

23. Ca(OH)2

24. Ca(OH)2
74.0 grams/mole

25. (NH4)3PO4

26. (NH4)3PO4
149.0 grams/mole

27. WATER H2O

28. What is the molar mass of water?

29. What is the molar mass of water?
18 grams / mole
18 grams per mole

30. What does this mean?

31. What does this mean?
It means that if you have 1.0 mole of water, you have 18.0 grams of water.

32. Anything else?

33. Anything else?
It also means that if you have 1.0 mole of water, you have 6.02 x1023 molecules of water.

34. What if you had 2.0 moles of water? How much is this?

35. What if you had 2.0 moles of water? How much is this?
It’s 36 grams of water.
It’s also x1024 molecules of water.

36. Mole to Gram Conversions
Example What is the mass in grams of 3.5 moles of copper? 3.5 moles Cu X grams/mole = grams

37. 3.5 moles of C

38. 3.5 moles of C
42 grams of carbon

39. 0.65 moles of K

40. 0.65 moles of K
grams of potassium

41. 1.2 moles of MgF2

42. 1.2 moles of MgF2
74.8 grams of MgF2

43. 4.2 moles of Ca(OH)2

44. 4.2 moles of Ca(OH)2
310.8 grams of Ca(OH)2

45. Gram to Mole Conversions
Example How many moles are there in 48 grams of O2? 48 grams of O2 ÷ 32 grams/mole = 1.5 moles

46. 5.0 grams of Ca

47. 5.0 grams of Ca
0.125 moles of Ca

48. 0.535 grams of Zn

49. 0.535 grams of Zn
moles of Zn

50. 36 grams of CO2

51. 36 grams of CO2
0.82 moles of CO2

52. 45 grams of (NH4)2S

53. 45 grams of (NH4)2S
0.66 moles of (NH4)2S

54. Atoms or molecules to mole conversions
Example How many moles are there in 3.5 x1020 atoms of gold? 3.5 x1020 atoms ÷ 6.02 x1023 atoms/mole = moles of gold

55. 1,000,000,000 atoms of copper

56. 1,000,000,000 atoms of copper
1.66 x10-15 moles of copper

57. 2.7 x1035 atoms of tin

58. 2.7 x1035 atoms of tin
4.49 x1011 moles of tin

59. Mole to Atoms or molecules conversions
Example How many atoms are there in 2.3 moles of carbon? 2.3 moles X 6.02 x1023 atoms/mole = 1.38 x1024 atoms of carbon

60. 0.4 moles of iron

61. 0.4 moles of iron
2.4 x1023 atoms of iron

62. 12.5 moles of water

63. 12.5 moles of water
7.5 x1024 molecules of water

64. Atoms or molecules to grams

65. 2.3 x1024 molecules of water

66. 2.3 x1024 molecules of water
68.7 grams of water

67. 7 trillion atoms of uranium

68. 7 trillion atoms of uranium
grams of uranium

69. Grams to atoms or molecules

70. 10 grams of CO2

71. 10 grams of CO2
1.37 x1023 molecules of CO2

72. grams of lead

73. grams of lead
2.18 x1017 atoms of lead