Unit 5 A Chapter 10 Chemical Quantities MoleMass

Mole – Mass Relationships n Use the molar mass of an element or compound

Converting Mass to Moles How many moles are in 92. 2 g of Fe

Try Known this… Unknown 0. 452 mol C 20 H 42 ? g C

Try this … Calculate the number of moles in 75. 0 g of magnesium

Slides: 5

Download presentation

Unit 5 A Chapter 10: Chemical Quantities Mole-Mass Relationships ABClark-Grubb

Mole – Mass Relationships n Use the molar mass of an element or compound to convert between mass and moles of a substance Converting Moles to Mass How many grams are in 9. 45 mol Al 2 O 3? Calculate Molar Mass First Al = 27. 0 g X 2 = 54. 0 g/mol O = 16. 0 g X 3 =+48. 0 g/mol 102. 0 g/mol 9. 45 mol Al 2 O 3 102. 0 g Al 2 O 3 1 mol Al 2 O 3 = 963. 9 g Al 2 O 3 = 964 g Al 2 O 3 rounded to the correct SIG FIGS

Converting Mass to Moles How many moles are in 92. 2 g of Fe 2 O 3? Calculate Molar Mass Fe = 55. 8 g X 2 O = 16. 0 g X 3 92. 2 g Fe 2 O 3 1 mol Fe 2 O 3 159. 6 g Fe 2 O 3 + = 111. 6 g/mol = 48. 0 g/mol 159. 6 g/mol = 0. 577694 mol Fe 2 O 3 = 0. 578 mol Fe 2 O 3 rounded to SIG FIGS

Try Known this… Unknown 0. 452 mol C 20 H 42 ? g C 20 H 42 Calculate Molar Mass C = 12. 0 g X 20 = 240. 0 g/mol H = 1. 0 g X 42 =+ 42. 0 g/mol 282. 0 g/mol 0. 452 mol C 20 H 42 282. 0 g C 20 H 42 1 mol C 20 H 42 = 127. 464 g C 20 H 42 = 127 g C 20 H 42 rounded to SIG FIGS

Try this … Calculate the number of moles in 75. 0 g of magnesium fluoride. * *Use your common ion table, find the formula. Calculate Molar Mass Mg = 24. 3 g X 1 = 24. 3 g/mol Mg. F 2 F = 19. 0 g X 2 + = 38. 0 g/mol 62. 3 g/mol 75. 0 g Mg. F 2 1 mol Mg. F 2 62. 3 g Mg. F 2 = 1. 20385 mol Mg. F 2 = 1. 20 mol Mg. F 2 rounded to SIG FIGS