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Mole Gangnam Style https://www.youtube.com/watch?v=HnRHBw-xjVo Grams # ions per formula unit formula unit 6.02 x 1023 Mr mole 6.02 x 1023 Mole Map atoms molecules # atoms per molecule Atoms (element) Dimensional Analysis How many moles are in 45.7 g of NO2? 1. Ask yourself the question – Can I convert directly from grams to moles? YES – molar mass has units of grams/mole Molar mass NO2 = 14.007 g + 2(15.999 g) = 46.005 g/mol 2. Start with your “given” from the original problem. 3. Use conversion factor that will allow you to “cancel” out grams and give you moles. 4. Calculate & express answer with correct sig. figs. and units! 45.7 g of NO2 1 mol 46.005 g = 0.993 mol Dimensional Analysis How many atoms are in 10.0 moles of Iron (Fe)? 1. Ask yourself the question – Can I convert directly from moles to atoms of an element? YES – there are 6.02 x 1023 atoms per mole 2. Start with your “given” from the original problem. 3. Use conversion factor that will allow you to “cancel” out grams and give you moles. 4. Calculate & express answer with correct sig. figs. and units! 10.0 mol Fe 6.02 x 1023 atoms Fe 1 mol Fe = 6.02 x 1024 Fe atoms Dimensional Analysis How many molecules are in 12.1 g of H2SO4? 1. Ask yourself the question – Can I convert directly from grams to molecules? NO– I have to go through moles 2. Start with your “given” from the original problem. 3. Use conversion factor that will allow you to “cancel” out grams and give you moles. 4. Calculate & express answer with correct sig. figs. and units! 12.1 g H2SO4 1 mol 6.02 x 1023 molecules 98.078 g 1 mol = 7.37 x 1022 molecules Dimensional Analysis How many atoms are in 210.0 g of H2SO4? NOTE: How many atoms are in 1 molecule of H2SO4? 2H + 1S + 4O = 7 total atoms per molecule 210.0 g H2SO4 1 mol 98.078 g 6.02 x 1023 molecules 1 mol 7 atoms 1 molecule H2SO4 = 9.023 x 1024 atoms Dimensional Analysis How many formula units are in 32.6 grams of potassium oxide? What is the formula for potassium oxide? 32.6 g K2O 1 mol 94.195 g K 2O 6.02 x 1023 f. units 1 mol = 2.08 x 1023 formula units Dimensional Analysis How many lithium ions are in 125g of lithium sulfate? What is the formula for lithium sulfate? Li2SO4 How many lithium ions are in one formula unit? 2 125 g Li2SO4 1 mol 109.944 g 2 Li ions 6.02 x 1023 f. units 1 mol 1 f. unit Li2SO4 = 1.37 x 1024 Li ions