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CHAPTER 11Introduction to Organic Molecules &
Functional Groups
General, Organic, & Biological ChemistryJanice Gorzynski Smith
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CHAPTER 11: Intro to Organic Molecules & Functional Groups
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Learning Objectives:
Difference between organic and inorganic molecules
Name characteristic features of organic compounds
Draw organic compounds, including skeletal structures
Identify common bond types, angles, and molecule
shapes
Name functional groups
Understand polarity and its effect on solubility and boiling
point
Explain the difference between fat and water soluble
vitamins
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CHAPTER 11: Intro to Organic Molecules & Functional Groups
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Lecture Outline:
① Define Organic Chemistry
② Review the shape of organic molecules
③ How to Draw organic compounds
④ Overview of functional groups
⑤ Review intermolecular forces
⑥ Review polarity
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Organic Chem Definition
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Organic Chemistry is the study of compounds containing carbon.
o Both naturally occurring and synthetic compoundso C, H, O, N, S, P, Halides (Cl, F, Br, I)
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GroupProblem
Brainstorm examples of organic and inorganic compounds.
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Organic Chem Definition
Smith. General Organic & Biolocial Chemistry 2nd Ed.
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Organic Chem Bonding
Smith. General Organic & Biolocial Chemistry 2nd Ed.
o Covalent Bond?
o Valence electron?
o Octet Rule?
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Organic Chem Bonding
Smith. General Organic & Biolocial Chemistry 2nd Ed.
A COVALENT BOND shares a pair of electrons between atoms.o non-metal to non-metal bond
o The OCTET RULE states that atoms of main group elements make bonds
by gaining, losing, or sharing electrons to achieve an outer shell
containing 8 electrons.
How many valence electrons do Carbon and Hydrogen have?Oxygen?Nitrogen?Sulfur?Phosphorous?Chlorine?
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GroupProblem
How many bonds does each atom need to satisfy the octet rule?
C
H
O
N
S
P
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GroupProblem
Draw these molecules:
Ethane: C2H6
Cyclohexane: C6H12
Propene: C3H6
Propyne: C3H4
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Molecule Shape Bond Angle
Smith. General Organic & Biolocial Chemistry 2nd Ed.
VSEPR Theory: The most stable arrangement of atoms in a molecule maximized the distance between atoms and lone pairs.
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GroupProblem
Draw the lewis dot structures for water and ethanol. How many lone pairs of electrons do they have?
What are the bond angles within the molecules?
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GroupProblem
Draw the lewis dot structure for ammonia. How many lone pairs of electrons does it have?
What are the bond angles within the molecule?
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Molecule Shape Drawing Molecules
Smith. General Organic & Biolocial Chemistry 2nd Ed.
SIMPLIFY!
C CCCH HHH
H HHH HH
CH3CH2CH2CH3
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GroupProblem
Practice: 1) convert to condensed structure 2) simplify further if possible 3) skeletal structure
Functional Groups Overview
16Smith. General Organic & Biolocial Chemistry 2nd Ed.
Alkane
Alkene
Alkyne
Aromatic
C − C
C = C
C = C
HydrocarbonFunctional
Groups
Functional Groups Overview
17Smith. General Organic & Biolocial Chemistry 2nd Ed.
Alkyl halides
Alcohols
Ethers
Amines
Single Bondto a
HeteroatomFunctional
Groups
Functional Groups Overview
18Smith. General Organic & Biolocial Chemistry 2nd Ed.
Aldehydes
Carboxylic Acids
Esters
Ketones
Amides
CarbonylFunctional
Groups
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GroupProblem
Identify all of the functional groups
pentabromodiphenyl ether
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GroupProblem
Identify all of the functional groups
Estradiol GenisteinA soy isoflavone
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GroupProblem
Identify all of the functional groups (other then alkanes) in Gliadin C29H41N7O9
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Properties of Organics Overview
Smith. General Organic & Biolocial Chemistry 2nd Ed.
o Organic compounds experience weaker
intermolecular interactions because they
form covalent bonds.
o no ion-ion interactions
o Usually clear or yellowish color
o Often a liquid or a gas at room temperature
o Lower melting points and boiling
points relative to ionic compounds
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Properties of Organics Polarity
Smith. General Organic & Biolocial Chemistry 2nd Ed.
The difference in electronegativity between two atoms bonded together creates a polar dipole moment. The more electronegative atom has a slight negative charge (more electron density).
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GroupProblem
What is the dipole moment of each bond, and what is the overall dipole moment for each molecule?
Water
Acetone
Isopropanol
Acetic Acid
Diethyl Ether
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Properties of Organics Intermolecular Forces
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Intermolecular Forcesweaker then intramolecular forces (bonding)
London Dispersion
Dipole-Dipole
Hydrogen Bonding
Instantaneous dipole-induced attractions that occur between all molecules, even non-polar.
Partial charges of polar compounds attract each other .
Strong dipole-dipole attraction when H is covalently bonded to a highly electronegative atom.
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Properties of Organics Intermolecular Forces
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Intermolecular Forcesweaker then intramolecular forces (bonding)
London Dispersion
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Properties of Organics Intermolecular Forces
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Intermolecular Forcesweaker then intramolecular forces (bonding)
Dipole-Dipole
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Properties of Organics Intermolecular Forces
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Intermolecular Forcesweaker then intramolecular forces (bonding)
Hydrogen Bonding
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GroupProblem
Rank the three intermolecular forces discussed in order of strength.
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Properties of Organics Solubility
Smith. General Organic & Biolocial Chemistry 2nd Ed.
LIKE DISSOLVES LIKEpolar molecules dissolve in polar solvents
nonpolar molecules dissolve in nonpolar solvents
Polar SolventsWater: H2OMethanol: CH3OHEthanol: CH3CH2OHAcetone: (CH3)2COAcetic Acid: CH3CO2HAmmonia: NH3
Acetonitrile: CH3CN
Nonpolar SolventsPentane: C5H12
Hexane: C6H14
Cyclohexane: C6H12
Benzene: C6H6
Toluene: CH3C6H5 Chloroform: CHCl3Diethylether: (CH3CH2)2O
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GroupProblem
Draw all of the solvents from the previous slide and prove they are polar or nonpolar.
Properties of Organics Water & Fat Soluble Vitamins
Smith. General Organic & Biolocial Chemistry 2nd Ed.
Which type of solvent would the following molecules dissolve in?
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Vitamin A
Vitamin B12
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Molecules BONDING: Lewis Bond Theory strategy to tackle problems
1) Start with the least electronegative element as the central element
2) Surround the central element with the bonding elements and indicate their initial electrons
3) Add extra electrons, from surrounding atoms, to the central atom to satisfy the octet rule
4) Use multiple bonds if necessary
NH H
H
NH3
NH H
H
NH H
H
Molecules BONDING: Lewis Bond Theory strategy to tackle problems
1) Initial electron bookkeeping:
2) Find the difference, this is the number of electrons that must be shared
3) ÷ 2 to know the # of bonds shared
4) Arrange atoms around the most electronegative element
5) Final electron bookkeeping:
NH
NH3
H
H
Need: 3x(1H x 2 e-) + (1N x 8 e-) = 14 e-
Have: 3x(1H x 1 e-) + (1N x 5 e-) = 8 e-
(14 e-) – (8 e-) = 6 e-
(6 e-) ÷ 2 = 3 bonds
NH H
H
NH H
H