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Honors Chemistry Unit 5 – The Mole. Lesson 2 – Molecular Molar Mass Book Section: 7-3 Objective: SWBAT use atomic molar masses to calculate molecular molar masses. Do Now: What is the molar mass of oxygen in grams?. Molecular Molar Mass.
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Honors ChemistryUnit 5 – The Mole Lesson 2 – Molecular Molar Mass Book Section: 7-3 Objective: SWBAT use atomic molar masses to calculate molecular molar masses. Do Now: What is the molar mass of oxygen in grams?
Molecular Molar Mass • Just like we can find the molar mass of an element, we can find the molar mass of a compound. • What is the molar mass of hydrogen? • 1.00794 g/mol • Units of grams per mole • What is the molar mass of oxygen? • 15.9994 g/mol • In this class, it is acceptable to round molar masses to the tenths place.
Molecular Molar Mass • Now, to find the molar mass of H2O. • Every mole of H2O has… • 2 mol of H • 1 mol of O • The molar mass of a compound is the sum of the molar masses of its elements. • MM H2O = 2(MM H) + 1(MM O) • MM H2O = 2(1.0 g/mol) + 1(16.0 g/mol) • MM H2O = 18.0 g/mol • 18 grams of water = 1 mol water = 6.02 x 1023 molecules of water
Molecular Molar Mass • Now, to find the molar mass of H2O. • Every mole of H2O has… • 2 mol of H • 1 mol of O • The molar mass of a compound is the sum of the molar masses of its elements. • MM H2O = 2(MM H) + 1(MM O) • MM H2O = 2(1.0 g/mol) + 1(16.0 g/mol) • MM H2O = 18.0 g/mol • 18 grams of water = 1 mol water = 6.02 x 1023 molecules of water
Practice - Easy • What is the molar mass of carbon dioxide, CO2? • How many molecules of carbon dioxide are in this amount?
Practice - Easy • What is the molar mass of carbon dioxide, CO2? • 44.0 g/mol • How many molecules of carbon dioxide are in this amount? • 6.02 x 1023 molecules
Practice - Medium • What is the molar mass of barium sulfate, BaSO4?
Practice - Medium • What is the molar mass of barium sulfate, BaSO4? • 233.4 g/mol • Neat Website: http://www.webqc.org/mmcalc.php • Can use to check your work!
Practice - Hard • What is the molar mass of iron (III) nitrate, Fe(NO3)3?
Practice - Hard • What is the molar mass of iron (III) nitrate, Fe(NO3)3? • 241.9 g/mol
Homework: #6-19 • This week: • Tuesday: Mole Conversions (7-3), Quiz 5-1, 5-2 (ten question quiz) • Wednesday: Keystone Biology Exam • Thursday: Keystone Biology Exam • Friday: The Mole Lab