AAMC Chemistry Question Pack Review Flashcards
What are the requirements for the formation of a H bond?
1) Hydrogen bond donor: A H bonded to a highly electronegative atom such as N or O
2) Hydrogen Bond acceptor: Electronegative atom with an available lone pair
An ebullator and boiling chip serve the same function in chemistry experiments. What is that function?
An ebullator and a boiling chip both serve to create air bubbles that will break the surface tension of a liquid being heated and prevent superheating and bumping
When trying to separate two enantomers with different boiling points in vacuum fractional distillation-what would be the benefit of heating at a slower rate?
It would allow each enantomer more time in the fractioning column and allow better separation
What is an Enantomer?
Chiral molecules that are mirror images of each other
Ex: Your hands are enantomers
What is a chiral center?
Tetrahedral atoms with 4 different substituants that will either have an R or S configuration
How do you assign priority to stereocenters?
1) Look up the atomic number of each atom bonded to carbon of interest, with the highest number being of the highest priority
2) If there is a tie between 2 or more atoms, use atoms at the 2 bond distance to break the tie
3) If there is still a tie, go to the 3 bond distance
What is the definition of a boiling point?
The boiling point of a liquid is a the temperature at which the vapor pressure equals the surface pressure
Atomic radius operates differently than most of the other periodic table trends. How?
Atomic radius operates opposite of the other periodic table trends.
It decreases from left to right and increases from top to bottom
Periodic Table Trends:
Ionization energy?
Increases from left to right and decreases from top to bottom
In a neutral atom, the number of protons = the number of ___________?
electrons
To find the amount of neutrons in an atom you would?
Subtract the atomic number from the atomic mass
An ionic bond is most likely to form between?
elements of a very high electronegativity and very low electronegativity
What is the difference between these compounds?
R-CHO
R-CH2OH
R-CHO is an adelhyde
R-CH2OH is a primary alchohol group
What are the 4 rules for recognizing a good nucleophile?
1) Charge: conjugate bases are always good nucleophiles
2) Electronegativity: Nucleophilicity decreases with increasing electronegativity
A H-C is far more nucleophilic than a H-F
3)Solvent: Hydrogen bonding solvents invert nucleophilicity
4)Steric Bulk: Nucleophilicity decreases with increasing steric bulk
Ex: A primary OH group is far more nucleophilic than a tertiary OH group
What is the formula for the number of possible peptides that one of each n-Amino Acid is?
n!(N factorial)
So n=3->3!=3x2x1=6 total
