Exam 1 Review PDF

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Exam 1 review for Chem0310 with Nelson...

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Exam 1 Review Chapter 1 1. Energy is everything! a. Almost every process is driven by an unstable state converting to a more stable state b. High energy  low energy 2. Bonding in Organic Compounds a. Atoms bond b/c they are more stable (lower energy) as molecules than they are as lone atoms b. Covalent: bonding interaction is derived from electron pair being shared between 2 atoms i. IMPORTANT: a new orbital is formed to house the shared electrons (molecular orbital) c. Ionic: bond results from complementary electrostatic interaction i. Important for reactions between atoms w/ very dissimilar electronegativities ii. Filled subshells = stable iii. Vacant subshells = reactive 1. High in energy and undergo processes to achieve stable configuration 3. Atomic & Molecular Orbitals a. Orbital describes energy of electron & region of space electron occupies b. ONLY relevant with electrons c. Atomic orbitals i. S,p,d, etc. d. Hybrid orbitals i. Orbitals combine to create new orbitals having characteristics of each contributing orbital ii. Sp3: 25%s, 75%p iii. Sp2: 33%s, 67%p 1. 1 unhybridized p orbital remaining iv. Sp: 50%s, 50%p 1. 2 unhybridized p orbitals remaining v. Most stable bonding configurations usually achieved using hybrid orbitals e. Molecular Orbitals i. Atomic orbitals that share same region of space & energy levels overlap to create new orbital associated w/ the new molecule 1. Strength of bonding interaction related to strength of orbital overlap ii. Total # orbitals must be conserved 1. AO=MO iii. Bonding VS anti-bonding MOs 1. When 2 orbitals overlap, 2 new orbitals are created

2. 1 lower in energy by E: Bonding MO a. Populating stabilizes molecules b. Make molecule less reactive 3. 1 higher in energy by E: Anti-bonding MO a. Populating destabilizes molecules b. Make molecule more reactive 4. Resonance Structures a. Resonance Structures: structures that differ in the way bonding & non-bonding electrons are distributed b. Characteristics i. Atoms are connected in the same order ( bond network does not change) ii. Resonance structures are localized representations of the resonance hybrid that is characterized by delocalized electron density Chapter 2 1. Acid-Base Reactions a. Exothermic reactions  yield favorable equilibria i. Releases energy b. Endothermic reactions  yield unfavorable equilibria c. Interpreting Keq i. Reactions at equilibrium favor more stable side ii. pKa: amount of disassociation 1. lower the pKa, stronger the acid d. How fast do we reach equilibrium? i. Magnitude of activation barrier ( G) dictates rate 1. G...