Organic Chemistry Flashcards

1
Q

Delta H = change in enthalpy

smaller enthaply =

A

smaller enthalpy= more stable.

more stable molecules need more energy to break its bond

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2
Q

Single bond = easiest bond to break
| |
Triple Bond = hardest to break

A

Single bond requires the least amount of energy to break

Triple bond requires the greatest amount of energy to break the bond.

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3
Q

CIS molecules ( Z) ( cyclic and alkenes) structures are polar or nonpolar ?

A

polar molecules

ODD number rings must always be polar when 2 substrates are attached.

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4
Q

Trans molecules ( E) molecules are polar or nonpolar

A

nonpolar

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5
Q

Pure alcohol has what kind of bonding

A

All Hydrogen bonding

when it is disturbed with any other compound, hydrogen bonding DECREASES

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6
Q

weight and hydrogen bonding affects what ?

A

Boiling temperature of a liquid

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7
Q

Enantiomer has how many chiral centers?

A

1

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8
Q

Diasteromers

A

have 2+ chiral centers

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9
Q

What are the types of isomers

A
  • constitutional - break into new molecule
  • conformational - rotate about a single bond
  • configurational = can be cis/trans and optical ( diasteromers and enantiomers)
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10
Q

what can enatiomers do with light?

A
rotate light (+) = dexi 
rotate light (-) = levi 

can only function in chiral enviroments?

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11
Q

When there are lone pairs on an atom, what happens to its bond angle

A

it decreases due to the electron replusion occuring , VESPR theroy because electrons take more space.

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12
Q

when a molecule can no longer undergo resonance and has distorted bond angles, what happens to that bond between the molecules?

A

the bond is weakened and can be easily broken.

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13
Q

Lithium aluminum hydride has what as its intermediate

A

an aldehyde!!

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14
Q

a Beta keto acid releases what when it is heated

A

a beta- ketoacid gets decarbozylated and loses the CO2 and it makes the amino acid into an amine.

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15
Q

Boiling point increases with what?

A

it increases with MW, length and increased hydrogen bonding

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16
Q

Strongest bond leads to the strongest boiling point

name the types of bond from strongest to weakest

A
  1. Ionic
  2. Hydrogen Bond
  3. Dipole-dipole
  4. Dispersion ( ie occurs with noble gases)
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17
Q

Degree of saturation

A

[(2n+2)-x)/2)

n=number of carbon
x=number of hydrogen

18
Q

Benedict test

A

a chemical assay that detects carbonyl unit of sugar and it recognizes a hemiacetal.

19
Q

What are the reagents of the strecker synthesis

A

aldehyde, ammonium chloride ( NH4Cl) potassium cyanide(KCN)

20
Q

What is the strecker synthesis used for?

A
  • 2 step process to make amino acids
  1. amino nitrile formation
  2. protonation of aminonitrale
  3. attack by water to turn the nitrile into carboxylic acid
21
Q

Gabriel ( Malonic ester) synthesis reagents

A

potassium phthalimide, diethyl bromomalonate

22
Q

relative configuration is retained if what?

A

bonds of the sterocenter are not broken. position of groups around chiral center are maintained.

23
Q

absolute configuration measures…

A

R /S

24
Q

Stronger acid leads to a what kind of base

A

negligible base

25
Q

strong base leads to what kind of acid

A

negligible acid

26
Q

Name the 7 strong acids

A
  • HCl
  • HBr
  • HI
  • H2SO4
  • H3PO4
  • HNO3
  • HClO4
27
Q

Specific rotation = observed rotation/(concentration of solution X length of tube)

A

if volumetric changes of solution, there will be a decrease of observed rotation and decrease concentration of solution.

28
Q

meso compounds

A

by definition are achiral but they do contain chiral carbons , have symmetry, and do not rotate polarized light

29
Q

conformational isomer

A

conformational isomers are mainly when you look down a C-C bond . think newtons projection.

30
Q

configurational isomer

A

rotate around a single bond .

31
Q

Diasteriomers can be seperated by chemical or physical separation

A

so in passage, if it talks about crystallzation as a means to seperate 2 compunds, it is definitely a diasterimer!

32
Q

Diasteriomers can be seperated by chemical or physical separation

A

so in passage, if it talks about crystallzation as a means to seperate 2 compunds, it is definitely a diasterimer!

33
Q

if a problem states that the configuration is retained, it does not mean that the absolute configuration is retained, the relative can be as well.

A

it basically means that there is no inversion of the molecules.

34
Q

define stereoselective

A

when a certain sterisisomer or a set of steroisomers predominiate as products

35
Q

define sterospecific

A

a reaction is sterospecific if different isomers lead to isomerically opposite products.

any reaction that is sterospecific is also stereoselctive but the converse it not true.

36
Q

anomer = only have 1 opposite configuration at 1 carbon

A

Enantiomer - differ at all chiral carons

37
Q

Racemization - occurs when substitution occurs at a chiral center

A

sp2 can not undergo racemization because it is not a chiral center

38
Q

PCC is a weak oxidier and it will only stop alcohol to aldehyde

chromic acid is a stronger oxiziging agent and will take alcohol to carboxlic acid -> only 1* and 2*

3* will not under go oxdiation

A

when you see lots of oxygen - think oxidizing

when yoif you want to see lots of Hydrogens - think reducing

39
Q

if you want to isolate a molecule what types of isolating mechanisms can you use?

A
  • Affinity Chromatography
  • size exclusion chromatography
  • Ion-exchnage chromatography
40
Q

Identify molecule - which methods can you use ?

A
  • NMR
  • Isoelectric focusing
  • IR
41
Q

if you have a product with decreased melting point, that means you have impurity . here is why:

A

if you have impurity, it will get in the way of the bonds forming which will leaded to a messed up crytal forming rather than pure. Pure srtyal will have a higher melting point ( similar to that found in literature)

if the crystal has a higher melting point that the one in literature, you probably have the wrong crystal.

42
Q

if something is aromatic, it should statisify 2 rules

A
  1. overlapping p orbitals

2. electrons must follow huckel’s rule such that 4n+2