FINAL Exam Flashcards
(38 cards)
pKa of Water
16
pKa of Ammonia
35–38
pKa of Methane
50
What does a high pKa value indicate?
- A weak acid
- A strong base
What does a low pKa value indicate?
- A strong acid
- A weak base
What does a high Ka value indicate?
- A strong acid
- A weak base
What does a low Ka value indicate?
- A weak acid
- A strong base
Components of Resonance
- Octet Rule
- Charge Compatibility
- Charge Separation
Features that Stabilize Negative Charge
- Electronegativity
- Atom Size (Polarizability)
- Hybridization
- Resonance
pKa of Hydrochloric Acid
–7
pKa of Hydrobromic Acid
–9
pKa of Hydroiodic Acid
–10
How does bulkyness/branchedness impact the boiling point of an alkane?
- A more bulky/branched alkane has a lower boiling point.
- A less bulky/branched alkane has a higher boiling point.
How does molecule size impact the boiling point of an alkane?
- A heavier alkane will have a higher boiling point.
- A lighter alkane will have a lower boiling point.
What determines the boiling point of a compound?
The strength/quantity of london-dispersion forces within the compound.
A molecule will more london-dispersion forces will have a higher boiling point.
What determines the melting point of a compound?
The ability of the compound to pack together into crystalline structures.
The more closely a compound can pack together, the higher its melting point will be.
Why are staggered Newton conformations more stable than eclipsed Newton conformations?
- In the staggered Newton conformation, electron-electron repulsion between adjacent substituents are minimized.
- In the eclipsed Newton conformation, electron-electron repulsion between adjacent substituent causes significant torsional strain.
Torsional Strain
The barrier to free rotation caused by electron-electron repulsion between nearby substituents.
Why does the anti-form Newton projection result in the most stable conformation?
The anti-form conformation places the largest substituents (with the greatest number of electrons) at the maximum distance from one another.
Steric Strain
The result of two substituents/molecules attempting the occupy the same region in space.
Why is a tertiary carbon radical more stable than a primary carbon radical?
- The tertiary carbon radical experiences more hyperconjugational inductive donation from neigboring σ bonds.
- The primary carbon radical possessese fewer adjacent C—R σ bonds that can inductively donate electrons.
Why does the Bromine radical only cleave the weakest bond of the substrate?
- The bromine radical is more stable due to the greater size of the atom, so it is less likely to cleave bonds.
- Creation of the bromine radical from Br—Br homolytic cleavage releases less heat, so less energy is available to cleave bonds of the substrate.
Why will the Chlorine radical potentially cleave all bonds of the substrate?
- The chlorine radical is less stable due to the smaller size of the atom, so it is more likely to cleave bonds.
- Creation of the chlorine radical from Cl—Cl homolytic cleavage releases more heat, so more energy is available to cleave bonds of the substrate.
Hammond’s Postulate
The more stable an intermediate structure is, the faster the product will form.
