Quiz #2

Question 1

Bronstead-Lowry acid

Answer 1

proton donor

Question 2

Bronstead-Lowry base

Answer 2

proton acceptor

Question 3

Lewis acid

Answer 3

accepts an electron pair; electrophile

Question 4

Lewis base

Answer 4

donates an electron pair; nucleophile

Question 5

Arrhenius acid

Answer 5

generates H+ in aqueous solutions

Question 6

Arrhenius base

Answer 6

generates OH- in aqueous solutions

Question 7

Lewis acid base reaction

Answer 7

Nucleophile (base) attacks the electrophile (acid)

The nucleophile uses its highest occupied molecular orbital and the electrophile uses its lowest unoccupied molecular orbital

Forms a covalent bond between the two species

Question 8

What kinds of molecules are lewis acids?

Answer 8

All cations

Anything with an incomplete octet

Question 9

pKa for strong acids

Answer 9

low

Question 10

pKa for weak bases

Answer 10

low

Question 11

pKa for strong bases

Answer 11

high

Question 12

pKa for weak acids

Answer 12

high

Question 13

Keq < 1

Answer 13

Reactants favored

Question 14

Keq > 1

Answer 14

Products favored

Question 15

Larger pKa

Answer 15

Weaker acid, stronger conjugate base

Question 16

Smaller pKa

Answer 16

Stronger acid, weaker conjugate base

Question 17

How does acidity affect the stability of the acid’s conjugate base?

Answer 17

More acidic acids have stabler conjugate bases

Question 18

What affects conjugate base stability?

Answer 18

1. Electronegativity (row)
2. Size of atom with the negative charge (column)
   3a. Delocalization, resonance
   3b. Delocalization, induction

Question 19

How does electronegativity affect acidity?

Answer 19

Acidity increases with electronegativity

Question 20

How does electronegativity affect conj. base stability?

Answer 20

Stability increases with electronegativity

Question 21

What determines carbon’s electronegativity?

Answer 21

It’s orbital hybridization state

sp3 < sp2 < sp
Order of increasing electronegatvity

Question 22

Order alkane, ene, and yne bonds in order of increasing acidity

Answer 22

ane < ene < yne

Question 23

How does atom size affect acidity?

Answer 23

Larger atoms are more acidic

HI is more acidic than HF

Question 24

How does resonance affect conj. base stability?

Answer 24

Resonance structures increase stability and therefore increase acidity

Question 25

How does induction affect conj. base stability?

Answer 25

Strong dipoles increase stability and therefore increase acidity

Question 26

What defines a conformational isomer?

Answer 26

Same molecular formula Same connectivity Different spatial arrangement of atoms Interconversions occur by rotation around single bonds

Question 27

Constitutional isomer

Answer 27

Same molecular formula Different connectivity

Question 28

Skew confomer

Answer 28

A conformer that is neither staggered nor eclipsed Found between 0 and 60 degrees

Question 29

Torsional strain

Answer 29

Resistance to twisting Occurs when nonbonded atoms separated by 3+ bonds are forced into eclipsed interactions Associated with the interactions of electrons in bonds Arises when a structure is forced to go from a more optimal confomer to a less optimal confomer

Question 30

Steric hindrance

Answer 30

The ability of groups to hinder access to a reaction site within a molecule due to the groups' size

Question 31

Gauche confomer

Answer 31

60 degree angle between non-H groups

Question 32

Rank the confomer positions from highest to lowest energy Include the angle between non-H groups

Answer 32

Total eclipse (0, 360) Eclipse (120, 240) Gauche (60, 300) Anti (180)

Question 33

Angular strain

Answer 33

Specific to ring forms Arises when a bond angle is either compressed or expanded away from its optimal value (optimal value is dictated by hybridization, sp = 180, sp2 = 120, sp3 = 109.5) Arises from a bond angle being compressed or expanded away from its optimal value Bond stretching isn't as easy as bond bending

Question 34

Ring strain

Answer 34

The combination of torsional strain and angle strain, found in ring forms

Question 35

How does ring strain relate to cycloalkane size?

Answer 35

Smaller rings (fewer carbons) have more ring strain. Cyclopropane has the most

Question 36

Ring puckering

Answer 36

When two carbons lean into each other, changing the rings shape and relieving ring (torsional+angular) strain

Question 37

General monocycloalkane formula

Answer 37

C(n) H(2n)

Question 38

General alkane formula

Answer 38

C(n) H(2n+2)

Question 39

General bicycloalkane formula

Answer 39

C(n) H(2n-2)

Question 40

What is strain?

Answer 40

A measure of energy stored in a compound due to structural distortion. It's the instability within a structure. It increases with internal energy levels

Question 41

Steric strain

Answer 41

Nonbonded interaction or Van der Waals strain Arises when nonbonded atoms (or atoms that are separated by at least 4 bonds) are forced closer to each other than their atomic (contact) radii allow

Question 42

Rank the cyclohexane confomers from highest energy to lowest

Answer 42

Half-chair Boat Twist boat Chair

Question 43

Diaxial interaction

Answer 43

A way to describe the relative stabilities of chair conformations with equatorial and axial substituents, int terms of their steric strain Refers to the steric strain arising from an axial substituent and an axial H or other group on the same side of a cyclohexane ring's chair confomer Sometimes called 1,3-diaxial interaction because the groups causing the strain are on carbons 1 and 3