1. Unit 9
Stoichiometry

2. formula mass
Atomic Mass Unit (u): unit of mass for measuring atoms. (1 u = 1/12th the mass of a carbon – 12 atom)

3. formula mass

4. formula mass
Example 2:
Find the mass of one molecule of Acetic acid (HC2H3O2).

5. Formula mass
Example 3: Find the formula mass of on molecule of magnesium phosphate.

6. Formula Mass
Example 4: Find the mass of one molecule of copper (II) sulfate pentahydrate.

7. Percent Composition

8. Percent composition
Example 2: What is the percent composition by mass of magnesium in Mg3(PO4)2?

9. Percent composition
Example 3: What is the percent by mass of water present in 1.0 mol of MgCl2 • 6H2O

10. Percent Composition
Example 4: A student obtained the following data to determine the percent by mass of water in a hydrate. Calculate the percent by mass of the water in the hydrated salt.
Mass of empty crucible + cover ………………………………….15.5 g
Mass of crucible + cover + hydrated salt ……………………….18.3 g
Mass of crucible + cover + anhydrous salt …………………… g

11. Empirical & Molecular Formulas

12. Empirical & molecular formulas
Example 1: Circle the empirical formulas in the list below; put an “X” over the molecular formulas. C2H4 HCl CH4 NO2 C3H9 C5H9 PCl4 P2O4 C6H12O6 C12H22O11

13. Empirical & molecular formulas
Example 1: Circle the empirical formulas in the list below; put an “X” over the molecular formulas. C2H4 HCl CH4 NO2 C3H9 C5H9 PCl4 P2O4 C6H12O6 C12H22O11

14. Empirical & molecular formulas
Example 2: For the following, give the empirical formula.
N2O4_________ C6H12O6 ________ C4H8O2 __________
C3H9 __________ C5H20 __________ C2H4 __________

15. Empirical & molecular formulas
Example 2: For the following, give the empirical formula.
N2O4_________ C6H12O6 ________ C4H8O2 __________
C3H9 __________ C5H20 __________ C2H4 __________

16. Empirical & Molecular Formulas
Example 3: A compound has the empirical formula of NO . If the molecular mass of this compound is g/mol, what is the molecular formula of the compound?

17. Empirical & Molecular Formulas
Example 4: A compound has a molar mass of 120 g/mol and an empirical formula of CH2O. What is the molecular formula of this compound?

18. The mole
Reflect:
What do the terms dozen, gross, and ream have in common?

19. The Mole Mole: Amount of substance Stands for a number = 6.02 x 1023
(just as a dozen = 12, a gross = 144, etc)
The mole allows us to compare numbers of particles (which may have different masses)

20. The Mole A mole of donuts = ____6.02 x 1023____donuts
A mole of baseballs = ____6.02 x 1023___baseballs
A mole of jelly beans = ___6.02 x 1023__ jelly beans

21. Ted Talk: How Big is a Mole?

22. The Mole

23. The Mole

24. The Mole

25. The Mole

26. Mole Conversions: 1 - Step
Reflect:
How many seconds are in 2 minutes?
What did you need to solve that problem?

27. Mole Conversions: 1 – Step

28. Mole Conversions: 1 - Step
The Mole
1 mole = Gram Formula Mass
1 mole = 6.02 x 10 23
1 mole = 22.4 Liters of a gas
The mole establishes the relationship between the gram and atomic mass unit.

29. Mole Conversions: 1 - Step
Directions: Complete each of the following mole conversions showing your work and labeling ALL numbers!
Example 1: If you have 11.2 g of NaCl, how many moles do
you have?

30. Mole Conversions: 1 - Step
Example 2: How many grams are in 2.50 moles of NaCl?

31. Mole Conversions:1 - Step
Example 3: How many molecules in 2 moles of water? Example 4: How many moles are in 1.81 x 1024 formula units of zinc nitrate?

32. Mole Conversions: 1 - Step
Example 5: How liters are in 4 moles of carbon
dioxide gas?
Example 6: How many moles are in 56 liters of
ammonia gas?

33. Mole Conversions: 1 - step
Avogadro’s Law: Equal volumes of a gas will contain the same number of particles. 1 mole of any gas = 22.4 Liters (molar volume)

34. Mole Conversions: 2 - Step
Reflect:
Look at the mole map in your notes. If I want to find out how many atoms are in a ten gram piece of copper wire, how many steps must I take?

35. Mole Conversions: 2 – Step
Example 1: How many grams are in 7.2 x 1022atoms of Ca?

36. Mole Conversions: 2 – Step
Example 2: How many sucrose molecules in 250 grams of sucrose? (Sucrose = C12H22O11)

37. Mole Conversions: 2 – Step
Example 3: What is the volume of 4.00 x 1024
molecules of methane (CH4)?

38. Mole Conversions: 2 – Step
Example 4: What is the mass of 64.5 liters of oxygen gas?

39. Mole Calculations: 2 – Step
Example 5: How many grams are in 13 L of carbon dioxide?

40. Mole Calculations: 2 – Step
Example 6: What is the volume, in liters, of 35.6 g of NH3 ?

41. Mole – Mole
Reflect:
If it takes 2 pieces of bread, 1 piece of cheese, 1 piece of ham, and 3 pieces of lettuce to make one sandwich…
2 Bread + 1 Cheese + 1 Ham + 3 Lettuce  1 Sandwich
How many sandwiches could I make with 4 pieces of bread?
How many pieces of cheese would I need to use up 6 slices of bread?

42. Mole – Mole

43. Mole to Mole
Practice Problem 1: In the following equation, how many moles of HCl are needed to react with 2.3 moles of Zn? 2HCl + Zn > ZnCl2 + H2

44. Mole to Mole
Practice Problem 2: In the following equation, how many moles of oxygen are needed to burn 0.52 moles of magnesium? 2 Mg + O > 2 MgO

45. Mole to Mole
Practice Problem 3: How many moles of Al(NO3)3 will be produced when 0.75 mole of AgNO3 reacts according to the following equation: AgNO3 + Al > Al(NO3)3 + Ag

46. Mole - Mole
Practice Problem 4: The Haber Process is shown below. How many moles of ammonia will be produced when 6 moles of hydrogen react according to the unbalanced equation below? (Hint: balance!) N2 + H2  NH3

47. Volume – Volume

48. Volume – Volume Practice Problem 5: If 0.38L of hydrogen gas reacts
with chlorine gas, what volume of HCl gas will be
produced?  
  H Cl2  2HCl

49. Volume – Volume Practice Problem 6: If 2.51 L of water vapor
decomposes, what volume of hydrogen gas will be
produced?  
 2H2O  2H2 + O2

50. Volume – Volume Practice Problem 7: What volume of nitrogen gas
will be consumed if 20.2 L of ammonia gas is
produced?
N H2  2NH3

52. Mass to Mass MOLES Mass Particles Volume 6.02 x 1023 particles
Molar mass
1 Mole
Mole Ratio

53. Mass to Mass
Practice Problem 1: Powdered Al reacts with iron (III) oxide to produce aluminum oxide and molten iron. What mass of aluminum oxide is produced when 2.3 grams of aluminum reacts with iron (III) oxide? 2Al + Fe2O > 2Fe + Al2O3

54. Mass to Mass
Practice Problem 2: What mass of NaOH is produced when 0.25 grams of Na reacts with water according to the following equation? 2Na + 2H2O > 2NaOH + H2

55. Mass to Mass
Practice Problem 3: In the following chemical equation you are given 125 grams of sodium azide. What volume of nitrogen gas is produced at STP? 2NaN > 2Na + 3N2 (g)

56. Mass to Volume
Practice Problem 4: Find the mass of Al required to produce 1.32 L of hydrogen gas at STP from the balanced chemical equation below: 2Al + 3H2SO > Al2(SO4)­3 + 3H2 (g)

57. Mass to Volume
Practice Problem 5: If 0.38L of hydrogen gas reacts with chlorine gas, what mass of HCl gas will be produced? H2 (g) + Cl2 (g) > 2HCl (g)