Chapter 1 (misc.)
How do you calculate formal charge on an atom?
Formal charge = # valence electrons - # "owned"
owned = 1 electron for bonds, 2 electrons for lone pairs
Acids are proton-_______.
donors
What is this? Drawing it may help.
RCOOR
Ester
Draw butane and cyclobutane.
4 carbons
Draw a resonance structure for
-OCH=CH2
(draw on board)
(on board)
What are the 4 factors that determine acid strength? List them in order of importance.
Atom (EN element with H-bonded to it)
Resonance (more resonance)
Hybridization (greater s-character)
Inductive effects (ewgs)
What is the difference between a primary, secondary, and tertiary amine?
Primary = connected to 1 R-group, R-NH2
Secondary = 2 R-groups, R-NH-R
Tertiary = 3 R-groups, R3N
What is the difference between steric, torsional, and angle strain?
Angle strain comes from squeezing or stretching bond angles away from their ideal shape
torsional strain happens when bonds are forced to line up directly behind each other (conTORT, eclipsed)
steric strain happens when large groups bump into each other in space because they are too crowded, electron cloud repulsion
Resonance structures: different ways of drawing the exact same molecule, just electrons moving around
Isomers: completely different molecules that just happen to share the same chemical formula
Draw the acid-base reaction between acetone and ethoxide, labeling the acid, base, conjugate acid, and conjugate base.
(draw on board, and it's in the notes)
What is the difference between melting point and boiling point trends in organic molecules?
Branching can sometimes lead to higher melting point if it makes the molecule more compact, whereas for bp branching lowers bp.
Type/strength of bond matters for both.
DEGREES OF UNSATURATION DAILY DOUBLE!
Draw 4 constitutional isomers of C7H14.
u = 1 so 1 ring or 1 double bond
Convert to a skeletal structure:
(CH3)2CHCH(NH2)CO2H
(draw)
(draw)
CH3OCH3 = Lewis base (electron donor), nucleophile
BF3 = Lewis ACid (electron ACceptor), electrophile
Which compound has the highest solubility in H2O?
A) CH3CH2CH2CH2CH3
B) CH3CH2CH2CH2COOK
C) CH3CH2CH2CH2COOH
D) CH3CH2CH2CH2COCH3
B) CH3CH2CH2CH2COOK
(ionic bonds dissociate better)
Draw four Newman projections for 1,2-dichloroethane (Cl–CH2–CH2–Cl), rotating 60 degrees each projection. Label the gauche conformer.
(draw)
Gauche is any 60 degree conformer.
Sketch the sigma bond orbitals for CH4 AND indicate the hybridization of each.
H = s
CH = sp3
Which is the strongest acid? (draw!)
A) CH3COOH
B) CF3COOH
C) CF3CH2OH
B) CF3COOH
How can you determine if a molecule can hydrogen-bond to itself?
It has H-bond donors (H-N or H-O) AND acceptors (lone pair).
Draw an energy diagram for the 1,2-dichloroethane (Cl–CH2–CH2–Cl) conformations you drew.
Highest Energy = 40 kJ/mol, Lowest= 0 kJ/mol
Intermediates = 20 kJ/mol and 6 kJ/mol
(draw)
anti = 0 kJ/mol (180 degrees)
eclipsed Cl/Cl = 40 kJ/mol
gauche = 6 kJ/mol (Cls further from each other) and 20 kJ/mol (Cls closer)