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Formula Mass & % Comp

Formula Mass & % Comp. It is NOT. A lack of intelligence. It IS. A lack of preparation. Formula Mass & Molecular Mass. Formula Mass. Formula mass is the total of all the atomic masses in a chemical formula. Formula Mass & Molecular Mass.

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Formula Mass & % Comp

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  1. Formula Mass & % Comp

  2. It is NOT A lack of intelligence

  3. It IS A lack of preparation

  4. Formula Mass& Molecular Mass

  5. Formula Mass Formula mass is the total of all the atomic masses in a chemical formula.

  6. Formula Mass& Molecular Mass Every molecular mass is a formula mass...

  7. Formula Mass& Molecular Mass but not every formula mass is a molecular mass.

  8. Formula Mass& Molecular Mass Can you explain why?

  9. Formula Mass& Molecular Mass Are molecules the only things that have chemical formulas?

  10. What is the formula mass of C2H5OH?

  11. What was the definition of a formula mass?

  12. The total of all the atomic masses in a chemical formula.

  13. The total of all the atomic masses in a chemical formula. C2H5OH X 2 X 1 X 6

  14. The units offormula mass are: A t o m i c M a s s U n i t s amuoru

  15. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u How to do formula mass calculations.

  16. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u Write the chemical symbols like this.

  17. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u Write the atomic mass of each.

  18. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u Multiply by the subscript of each.

  19. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u Equals

  20. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u Circle your answer. Show the units.

  21. Formula Mass Calculation C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u This is a molecular mass

  22. Formula Mass Calculation SO4+2 S = 32 X 1 = 32 O = 16 X 4 = 64 96 u This is NOT a molecular mass

  23. Formula Mass Calculation SO4+2 S = 32 X 1 = 32 O = 16 X 4 = 64 96 u It is an ionic mass

  24. Practice Calculating Formula Mass

  25. What is the formula mass of iron (II) sulfate?

  26. FeSO4

  27. FeSO4 Fe S O

  28. FeSO4 Fe = 56 S = 32 O = 16

  29. FeSO4 Fe = 56 X 1 S = 32 X 1 O = 16 X 4

  30. FeSO4 Fe = 56 X 1 = 56 S = 32 X 1 = 32 O = 16 X 4 = 64

  31. FeSO4 Fe = 56 X 1 = 56 S = 32 X 1 = 32 O = 16 X 4 = 64 152 u

  32. Formula Mass Homework Assignment

  33. Hydrated Crystals Crystals that have water molecules chemically bonded to the ions in the crystal.

  34. This occurs when a highly ionic substance crystallizes from a water solution.

  35. Although these crystals are solids, the water molecules can be forced out of the crystal lattice by heating.

  36. CuSO4 5H2O The formula for "hydrated" copper (II) sulfate above indicates there are 5 water molecules for every 1 copper (II) sulfate.

  37. CuSO4 5H2O What is the formula mass of copper (II) sulfate pentahydrate HINT: treat water as a separate element in the formula.

  38. CuSO4 5H2O Cu = 1 X 64 = 64 S = 1 X 32 = 32 O = 4 X 16 = 64 H2O = 5 X 18 = 90 250 amu

  39. ChemLab 9 How much water (in grams) is in 5 grams of copper (II) sulfate pentahydrate?

  40. CuSO4 5H2O looks something like this:

  41. Anhydrous CuSO4 looks something like this:

  42. Percentage Composition Each element makes up a % of the substance.

  43. Percentage Composition Add one step to a formula mass calculation.

  44. Percentage Composition What is the percentage composition of C2H5OH?

  45. Percentage Composition C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u

  46. Percentage Composition C2H5OH C = 12 X 2 = 24 H = 1 X 6 = 6 O = 16 X 1 = 16 46 u Now divide EACH atomic mass by the formula mass.

  47. Percentage Composition C2H5OH C = 12 X 2 = 24 / 46 = 52 % C H = 1 X 6 = 6 / 46 = 13 % H O = 16 X 1 = 16 / 46 = 35 % O 46 u This is the answer

  48. Practice Calculating Percentage Composition

  49. What is the complete percentage composition of sulfuric acid?

  50. H2SO4 H = 1 X 2 = 2 S = 32 X 1 = 32 O = 16 X 4 = 64 Work as a formula mass problem 98

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