L01S07_Stochiometry 01-17-07

L01S07_Stochiometry 01-17-07 - Chem 1A, L1: "Atoms,...

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Unformatted text preview: Chem 1A, L1: "Atoms, Molecules, Stoichiometry" Heino Nitsche http://chem1a.berkeley.edu/~chem1a/ Lab Instructor : Dr.Jennifer Shanoski, Latimer Hall Shanoski, Enrollment: Dr. Robert Lamoreaux, 211 Latimer Lamoreaux, Demo Supervisor: Lonnie Martin Head TAs: Greg Dallinger, Irena Dragojevic (E-Tech) Dallinger, (E 2006 Pines,Kubinec,Nitsche, UCB L1-1 Welcome to Chem1A ChemQuiz 1.0 How many years of chemistry did you have in high school? 1) 0 2) 0.5 3) 1 4) 2 2006 Pines,Kubinec,Nitsche, UCB L1-2 Summary 2H2 Energy Reactants + Chemical Reactions O2 2H2O High Road (barrier) Products Reaction Coordinate 2001 UC Regents L1-4 Relative Atomic and Molecular Mass H 1.01 12C 2H2 + O2 2H2O Al 26.98 P 30.97 Fe 55.85 Pb 207.2 H2 2.02 O2 32.00 H2O 18.02 CO2 44.01 12.00 C 12.01 O 16.00 2 molecules + 1 molecule 2 moles + 1 mole 2 grams + 16 grams 2 molecules 2 moles 18 grams 2006 A.Pines, M.Kubinec, H. Nitsche UCB 1 Chem 1A, L1: "Atoms, Molecules, Stoichiometry" Chemical Reactions 2H2 Energy Reactants Products Reaction Coordinate 2006 Pines,Kubinec,Nitsche, UCB + O2 2H2O Transition State High Road (barrier) (barrier) L1-4 Scanning Probe Microscopy Can Image Single Atoms Image of a ring of cobalt atoms placed on a copper surface An Scanning Tunneling Microscopy (STM) image of nickel atoms placed on a copper surface. 2006 Pines,Kubinec,Nitsche, UCB L1-5 Stoichiometry Relationships between quantities of matter that participate in chemical reactions. Macroscopic Bulk matter NA Microscopic Atoms, Molecules Avogadro's Number: NA = 6.022 x 1023 Avogadro' NA atoms in 12.00 g 12C= one Mole Molar Mass (g/mol) 2006 Pines,Kubinec,Nitsche, UCB L1-6 2006 A.Pines, M.Kubinec, H. Nitsche UCB 2 Chem 1A, L1: "Atoms, Molecules, Stoichiometry" is assigned exactly 12 atomic mass units (amu or u) Masses of all other atoms are given relative to this standard Atomic masses are averages of isotopic masses Relation between amu and grams (6.022 x 1023 atoms) (12amu/atom) = 12 g 6.022 x 1023 amu = 1 g 1 amu = 1.661 x 10-24 g = 1.661 x 10-27 kg 2006 Pines,Kubinec,Nitsche, UCB 12C Atomic Mass and Mass Units L1-7 Relative Atomic and Molecular Mass H 1.01 12C Al 26.98 P 30.97 Fe 55.85 Pb 207.2 H2 2.02 O2 32.00 H2O 18.02 CO2 44.01 L1-8 12.00 C 12.01 O 16.00 2006 Pines,Kubinec,Nitsche, UCB ChemQuiz 1.1 What mass (g) of methane is required to react completely with 4 g of oxygen as shown? CH4 + 2 O2 CO2 + 2 H2O Relative masses: O2 = 2 x CH4 1) ~1 2006 Pines,Kubinec,Nitsche, UCB 2) ~2 3) ~4 g L1-9 2006 A.Pines, M.Kubinec, H. Nitsche UCB 3 Chem 1A, L1: "Atoms, Molecules, Stoichiometry" Molecules, Moles, Mass 2H2 + O2 2H2O 2 molecules + 1 molecule 2 moles + 1 mole 2 grams + 16 grams 2006 Pines,Kubinec,Nitsche, UCB 2 molecules 2 moles 18 grams L1-11 Stoichiometry Relationships between quantities of matter that participate in chemical reactions. 2H2 Energy + O2 2H2O Transition State High Road (barrier) Low Road (catalyst) Reactants Products Reaction Coordinate 2006 Pines,Kubinec,Nitsche, UCB L1-12 ChemQuiz 1.2 Following the reaction of 1 mole H2 and 2 moles O2 which species has the greatest number of moles? 1) H2 2006 Pines,Kubinec,Nitsche, UCB 2) O2 3) H2O L1-13 2006 A.Pines, M.Kubinec, H. Nitsche UCB 4 Chem 1A, L1: "Atoms, Molecules, Stoichiometry" ChemQuiz 1.3 2 moles of an oxide of hydrogen release 1 mole oxygen, leaving pure water. oxygen, water. Which is the oxide? 1) HO 2006 Pines,Kubinec,Nitsche, UCB 2) H2O2 3) H2O3 L1-15 ChemQuiz 1.4 M2CO3 M2O + CO2 Consider the decomposition of 1 gram each of Li2CO3 and Na2CO3. What are the relative quantities of CO2 produced? (Molar Mass: Li < Na ) 1) Li < Na 2006 Pines,Kubinec,Nitsche, UCB 2) Li = Na 3) Li > Na L1-17 Lecture Complete 2006 Pines,Kubinec,Nitsche, UCB L1-19 2006 A.Pines, M.Kubinec, H. Nitsche UCB 5 Chem 1A, L1: "Atoms, Molecules, Stoichiometry" Atomic Mass and Mass Units Relation between amu and grams (6.022 x 1023 atoms) (12amu/atom) = 12 g 6.022 x 1023 amu = 1 g 1 amu = 1.661 x 10-24 g = 1.661 x 10-27 kg Example: Natural carbon m(13C)/m(12C) = 1.0836129 m(13C) = (1.0836129)(12 amu) = 13.003355 amu 98.89 % 12C, 1.11 % 13C m(natural C) = (0.9889)(12 amu) + (0.0111)(13.0034 amu) = 12.01 amu 2006 Pines,Kubinec,Nitsche, UCB L1-20 2006 A.Pines, M.Kubinec, H. Nitsche UCB 6 ...
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This note was uploaded on 08/19/2009 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at University of California, Berkeley.

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