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The Mole Concept Chemistry
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What is a mole? The mole is a unit used to measure very small quantities – Such as atoms, particles, molecules, ions, etc. – One mole = 6.022 x 10 23 The mole is similar to the concept of a dozen – One dozen = 12
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One mole can represent many things! One dozen would be… 12 eggs 12 atoms 12 chemistry teachers One mole would be… 6.02 x 10 23 eggs 6.02 x 10 23 atoms 6.02 x 10 23 chemistry teachers!
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Amadeo Avogadro The concept of the mole is attributed to Avogadro, and is referred to as Avogadro’s number
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A Mole Can Represent Anything Atoms Molecules Particles Planets Coins
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Mole Conversions Example Problems 1.If I have 3 moles of He gas, how many particles is this? 2.If I have 8.0 x 10 24 atoms of iron, Fe, how many moles is this? 1.81 x 10 24 particles He 13.3 mol Fe
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Molar Mass The mass of one mole of a substance – Based on their atomic masses on the periodic table – By convention, we will round atomic masses to 3 sig figs – Molar masses can be used as a conversion factor Molar Mass has units of grams per mole (or g/mol)
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Molar Mass Example Problems 1.What is the molar mass of iron? 2.How many grams of iron are there in 8.00 moles? 55.8 g/mol Fe 446 g Fe
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Molar Mass Example Problems 3.How many moles are in 10.0 grams of magnesium? 4.How many moles are in 5.3 grams of boron? 0.412 mol Mg 0.491 mol B
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Molar Mass Practice Problems 1.How many grams of sulfur are there in 2.5 moles? 2.How many grams of aluminum are there in 2.00 moles? 80.3 g S 54 g Al
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Molar Mass Practice Problems 3.How many moles are there in 3.4 grams of carbon? 4.How many moles are there in 2.00 grams of neon? 0.283 mol C 0.099 mol Ne
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Molar Mass of Molecules Using the molar mass for each element, find the total molar mass of a molecule Example Problems 1.What is the molar mass of H 2 O? 2.What is the molar mass of CO 2 ? 18.02 g/mol H 2 O 44 g/mol CO 2
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Molar Mass of Molecules Practice Problems 1.What is the molar mass of C 3 H 8 ? 2.What is the molar mass of CH 3 I? 44.1 g/mol C 3 H 8 142 g/mol CH 3 I
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Molar Mass of Molecules Example Problems 1.If I have 5.00 grams of NaCl, how many moles is this? 2.If I have 4.50 moles of water, H 2 O, how many grams is this? 0.0901 mol NaCl 81.1 g H 2 O
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Molar Mass of Molecules How many particles are there in 3.00 grams of ammonia (NH 3 )? 1.06 x 10 23 particles NH 3
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Molar Mass of Molecules Practice Problems 1.How many moles are in 1.2 grams of methane gas (CH 4 )? 2.How many grams are in 4.3 moles of propane (C 3 H 8 )? 0.0665 mol CH 4 189 g C 3 H 8
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Molar Mass of Molecules How much do 1.3 x 1024 atoms of H2O weigh (in grams)? (2 steps!) 0.389 g H 2 O
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