1. CHAPTER 7 CHEMICAL FORMULA

2. Remember… The Mole Is a Counting Unit The mole is used to count out a given number of particles (atoms, molecules, formula units, ions, or electrons) The mole is just one kind of counting unit: 1 dozen = 12 objects 1 hour = 3600 seconds 1 mole = 6.022  10 23 particles

3. Visual Concepts The Mole Chapter 7

4. Calculating Molar Mass Also known as: Gram Formula Mass G.F.M.

5. Molar Mass How much the compound weighs Just add everything up using the mass from the P.T. Example:

6. Molar Mass ZnCl 2 = Zn + 2 Cl = 65.39 + 2 (35.45) = 65.39 + 70.90 = 136.29 g / mol ZnSO 4 = Zn + S + 4 Oxy = (65.39) + (32.07) + 4 (16.00) = 161.46 g / mol

7. Molar Mass (NH 4 ) 2 SO 4 = 2 N + 8 H + S + 4 Oxy = 2(14.01) + 8 (1.01) + 32.07 + 4 (16.00) = 28.02 + 8.08 + 32.07 + 64.00 = 132.17 g / mol

8. Mol – g Conversions Using Molar Masses

9. Molar Mass Conversions Sample Problem A: How many grams are in 2.50 mol of oxygen gas, O 2 ?

10. Molar Mass Conversions Sample Problem A: How many grams are in 2.50 mol of oxygen gas, O 2 ? Step 1: Start with what you know from the problem. 2.50 mol O 2 = X g

11. Molar Mass Conversions Sample Problem A: How many grams are in 2.50 mol of oxygen gas, O 2 ? Step 2: Determine the molar mass of your compound. O 2 = 2 Oxy 2 (16.00) 1 mol = 32.00 g

12. Molar Mass Conversions Sample Problem A: How many grams are in 2.50 mol of oxygen gas, O 2 ? Step 3: Set – up the problem so the units cancel out. 2.50 mol O 2 = X g 1 mol 32.00 g X = 80.0 g

13. Sample Problem B Ibuprofen, C 13 H 18 O 2, is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol. If the tablets in a bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle?

14. Sample Problem B Ibuprofen, C 13 H 18 O 2, is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol. If the tablets in a bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle? Step 1: Start with what you know from the problem. 33 g C 13 H 18 O 2 = X mol

15. Sample Problem B Ibuprofen, C 13 H 18 O 2, is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol. If the tablets in a bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle? Step 2: Determine the molar mass of the compound. 206.31 g = 1 mol

16. Sample Problem B Ibuprofen, C 13 H 18 O 2, is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol. If the tablets in a bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle? Step 3: Set-up the problem so the units cancel out. 33 g C 13 H 18 O 2 = X mol 206.31 g 1 mol X = 0.16 mol C 13 H 18 O 2

17. Mole – Mass Conversions Team Review

18. Question # 1 Calculate the molar mass of barium nitrate. Ba(NO 3 ) 2 261.35 g / mol

19. Question #2 Calculate the molar mass of lithium nitride. Li 3 N 34.92 g / mol

20. Question # 3 Calculate the molar mass of magnesium phosphate. Mg 3 (PO 4 ) 2 262.87 g / mol

21. Question # 4 Calculate the molar mass of iron (III) oxide. Fe 2 O 3 159.70 g / mol

22. Question #5 How many moles are found in 100. g of barium nitrate? 0.383 mol Ba(NO 3 ) 2

23. Question # 6 How many moles are found in 24.3 g of lithium nitride? 0.696 mol Li 3 N

24. Question # 7 What is the mass found in 2.25 mol iron (III) oxide? 359.32 g Fe 2 O 3

25. Question # 8 What is the mass found in 1.30 mol magnesium phosphate? 341.73 g Mg 3 (PO 4 ) 2

26. Question # 9 How many molecules are found in 6.4 mol NH 3 ? 3.85 x 10 24 molecules NH 3

27. Question # 10 How many moles are found in 1.85 x 10 24 molecules of water? 3.07 mol H 2 O

28. Question # 11 What is the mass of 2.30 x 10 23 molecules of CO 2 ? 16.81 g CO 2

29. Question # 12 How many molecules are found in 25 g N 2 ? 5.37 x 10 23 molecules of N 2

30. Percent Composition

31. Visual Concepts Percentage Composition Chapter 7

32. Percent Composition

33. Sample Problem C Find the percent composition of copper (I) sulfide, Cu 2 S.

34. Sample Problem C Find the percent composition of copper (I) sulfide, Cu 2 S. Step 1: Use the formula to determine the molar mass of the compound. Cu 2 S = 2 Cu + S 2 (63.55) + 32.07 159.20 g / mol

35. Sample Problem C Find the percent composition of copper (I) sulfide, Cu 2 S. Step 2: Determine the % composition of the 1 st element. Cu = mass of Cu x 100 Total molar mass

36. Sample Problem C Find the percent composition of copper (I) sulfide, Cu 2 S. Step 3: Determine the % composition of the 2 nd element. S = mass of S x 100 Total molar mass

37. Class Quiz

38. Chapter 7 Standardized Test Preparation Multiple Choice 1.Which of the following compounds does not contain a polyatomic ion? A.sodium carbonate B.sodium sulfate C.sodium sulfite D.sodium sulfide

39. Chapter 7 Standardized Test Preparation Multiple Choice 2.The correct formula for ammonium phosphate is A.(NH 4 ) 3 PO 4. B.(NH 4 ) 2 PO 4. C.NH 4 PO 4. D.NH 4 (PO 4 ) 2.

40. Chapter 7 Standardized Test Preparation Multiple Choice 3.When writing the formula for a compound that contains a polyatomic ion, A.write the anion’s formula first. B.use superscripts to show the number of polyatomic ions present. C.use parentheses if the number of polyatomic ions is greater than 1. D.always place the polyatomic ion in parentheses.

41. Chapter 7 Standardized Test Preparation 4.The correct name for NH 4 CH 3 COO is A.ammonium carbonate. B.ammonium hydroxide. C.ammonium acetate. D.ammonium nitrate. Multiple Choice

42. Chapter 7 Standardized Test Preparation 5.Which of the following is the correct formula for iron(III) sulfate? A.Fe 3 SO 4 B.Fe 3 (SO 4 ) 2 C.Fe 2 (SO 4 ) 3 D.3FeSO 4 Multiple Choice

43. Chapter 7 Standardized Test Preparation Multiple Choice 1.Which of the following compounds does not contain a polyatomic ion? A.sodium carbonate B.sodium sulfate C.sodium sulfite D.sodium sulfide

44. Chapter 7 Standardized Test Preparation Multiple Choice 2.The correct formula for ammonium phosphate is A.(NH 4 ) 3 PO 4. B.(NH 4 ) 2 PO 4. C.NH 4 PO 4. D.NH 4 (PO 4 ) 2.

45. Chapter 7 Standardized Test Preparation Multiple Choice 3.When writing the formula for a compound that contains a polyatomic ion, A.write the anion’s formula first. B.use superscripts to show the number of polyatomic ions present. C.use parentheses if the number of polyatomic ions is greater than 1. D.always place the polyatomic ion in parentheses.

46. Chapter 7 Standardized Test Preparation 4.The correct name for NH 4 CH 3 COO is A.ammonium carbonate. B.ammonium hydroxide. C.ammonium acetate. D.ammonium nitrate. Multiple Choice

47. Chapter 7 Standardized Test Preparation 5.Which of the following is the correct formula for iron(III) sulfate? A.Fe 3 SO 4 B.Fe 3 (SO 4 ) 2 C.Fe 2 (SO 4 ) 3 D.3FeSO 4 Multiple Choice