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Unformatted text preview: Select Disease/Drug Today! Begin work on the Literature assignment. Self Assessment Reminder Self Assessment Reminder You must take the IMAGE assessment instrument no later than midnight Friday evening (Sept. 24) in order to give the Center for Life Calling & Leadership time to process all the submissions and print copies to bring to class on Oct. 8. Instructions on our Blackboard site within the Assignments tab STOICHIOMETRY STOICHIOMETRY Chemicals Consumed & Produced Chapter 2.9 STOICHIOMETRY STOICHIOMETRY If we know A + B ⇔ C + D, why is it important to know a A + b B ⇔ c C + d D ??? Why do we care if: 1 Pb(NO 3 ) 2 + 2 LiI ==> 2 LiNO 3 + 1 PbI 2 ????? Theoretical – Complies with Law of Conservation of Mass Practical – Allows for prediction of yields STOICHIOMETRY STOICHIOMETRY • If we know A + B ⇔ C + D, why is it important to know a A + b B ⇔ c C + d D ??? How do we count out these atoms and molecules, when we usually determine their mass in grams, not numbers of molecules? MOLE MOLE Scientists use a quantity called a mole , which is 6.022 X 10 23 particles (atoms, molecules, ions), just like a dozen is 12 of anything . Thus, the formula 4Al(s) + 3O 2 (g) ==> 2Al 2 O 3 (s) would be taken to mean: Four moles of aluminum atoms will react with three moles of oxygen molecules to form two moles of aluminum oxide formula units . 256g S 8 342g Sugar C 12 H 22 O 11 201g Hg 64g Cu 18g H 2 O 37% 13% 20% 30% 1. 1. The weight of one atom or molecule of each is similar The weight of one atom or molecule of each is similar 2. 2. They are all about 1 mole of that substance They are all about 1 mole of that substance 3. 3. They all contain the same mass % of oxygen They all contain the same mass % of oxygen 4. 4. They all started with one mole of reactants They all started with one mole of reactants What do the following samples have in common? What do the following samples have in common? WHY BOTHER? WHY BOTHER? What are some advantages of using this quantity that is equivalent to 6.022 X 10 23 of anything?...
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