CHEM 210 Study Guide Exam 1

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CHEM 210 Study Guide Exam 1 Powered By Docstoc
					Exam 1 - Study Guide
CHEM 210
CHAPTER 1: Structure and Bonding
1. Bonding
     a. Know the difference between ionic, polar covalent and covalent bonds
     b. What is a covalent bond? Why is this arrangement favorable for atoms?
     c. Be able to draw proper Lewis structures for a given formula, including the cases where
         multiple bonds must be formed or formal charges exist
     d. You should know Table 1.1 very well. Realize that you can combine any two single bonds
         shown into a double bond (with the requisite change in hybridization) and keep the same
         formal charges.
     e. Know cases where the octet rule is not in operation (i.e. every element in the periodic table
         other than C, N, O and X)
     f. Be able to draw contributing resonance structures where possible – remember the rules!
     g. Do not be overly concerned with resonance hybrids as yet, but know what they are and
         what they mean
     h. Be comfortable with the nomenclature for partial charges – δ + or δ -
     i. Know why atomic orbitals hybridize and what hybridization means
     j. Know the hybrid orbital types for C, N, and O – sp3, sp2 and sp
              What happens to the remaining unhybridized p orbitals in the case of sp2 and sp;
              Know the shapes of these orbitals
     k. Know the bonding models for ethane, ethylene and acetylene and be able to apply them to
         other combinations of atoms C-O, N-O, C-N, etc.
     l. Be able to sketch these bonding models
     m. Be able to give the bond polarity for any bond (exam has a periodic table)
     n. Be able to predict the overall polarity for small molecules

2. Structure:
       a. Know what constitutional isomers are and be able to draw them
       b. Know the difference between VSEPR geometry and molecular geometry
       c. Know and be able to use the table in 1.6B to quickly determine geometry based on the
           number of groups
       d. Be able to predict bond angles based on hybridization
       e. Know the general trend for the length and strength of bonds in ethane, ethylene, and
           acetylene and why the trend has anomalies and what they mean (i.e. why isn’t a C=C twice
           the energy of a single bond?)
       f. Know how to draw condensed and skeletal structures – remember that I do not stress the
           condensed structures for very complicated systems – but you should know how to do
           simple problems as well as know the condensed formula for the carboxylic acid, aldehyde,
           ketone and ester functional groups (i.e. –CHO is aldehyde)

CHAPTER 2 – Acids and Bases:
  1. Know the Bronstead and Lewis definitions for acids and bases
  2. Know how pKA describes acid strength (-log KA, small numbers indicate stronger acids, etc.)
  3. Table 2.1 should be roughly memorized for the rest of the course
  4. Be able to predict the outcome of an acid base reaction given the pKAs for the acid and
     conjugate acid (use acid pKA and conjugate acid pKA)
   5. Be able to compare the acidity of two species.
                     i. Remember, the most important factor in how able a molecule is to donate a
                        proton is the stability of the corresponding conjugate base, A-
                    ii. This anion can be stabilized by:
                        1) element effects,
                        2) inductive effects,
                        3) resonance effects
                        4) hybridization effects –
                   iii. Be comfortable with the examples we gave in class of these effects and be
                        able to make decisions on which of two similar molecules is more acidic than
                        the other
   6. Know the arrow formalism for electron movement in both Bronstead and Lewis acid-base
   7. Be able to identify nucleophiles and electrophiles

CHAPTER 3 – Introduction to Functional Groups
  1. Know all of the organic functional groups (Table 3.1, 3.2, 3.3)
  2. Know the structural features of each, and what they indicate about reactivity
  3. Know the four major inter-molecular forces and what they indicate about the physical
     properties of each of the organic functional groups
  4. Back to Chapter 1 material – you should be able to predict the hybridization of any atom in any
     of the functional groups as well as the commensurate bond angles and bond strengths, as well
     as bond polarity

Disclaimer – a study guide is simply that – a guide to help you outline and organize your
preparation for the exam. There may be material on the exam not explicitly mentioned here
that will be used to test your application of knowledge.

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