Orgo Midterm 1

how would you draw a acid and base (the process of the electron getting accepted and like that)

does having a negative make something a strong base or acid

• it makes it a strong base because it really wants to be neutral so it wants that hydrogen

does having a positive charge make something a stronger acid or base

• it makes it a stronger acid because it wants to be neutral so it wants to get rid of that positive charge

when ARIO fails, look at formal charges and solvating effects

if you are given the base and told to see if it is a strong acid don’t change it and just look at it how it is

only what type of electrons can make bonds

• UNPAIRED

what does an unhybridized p orbital mean

• it isn’t being used

• ex. sp2: _ _ _ (unhybridized one) p

• _ s

always end up with what you start with in hybridization

more s character = held closer to the nucleus

the more dipole moments a molecule has the more polar it is

what type of bonds have linear geometry

• triple

difference between valence bond theory and molecular orbital theory

• valence bond looks at bonds separately but molecular orbital looks at it as a whole

what is the different between organic and inorganic compounds

• organic ones have carbon

  • they make up everything (food, clothes)

when scientists did what experient did they find that organic compounds didn’t just come from human beings

• heating up ammonium cyanate to make urea

how to say the number of bonds that can be made (4, 3,2, 1)

• tetravalent

  • 4

• trivalent

  • 3

• divalent

  • 2

• monovalent

  • 1

what is a constiutional isomer

• compounds with the SAME molecular formula but different structures

what do you need for a molecule to do a reaction

• a collision

• bonds to break and form

• for ex. melting is only a physical reaction because it is the same thing just separating

what electrons do we care about in orgo and why

• VALENCE!

• we care about electron flow

  • where they are going, why they give electrons, and why they accept them too

• because they are the ones involved in bonding

• when drawing a lewis dot structure give each bond 2 electrons

formal charge equation

• valence - electrons around

NEVER DRAW ANYTHING INSIDE THE V!!!!!!!!!!!

How to draw triple bonds so it will be accepted

• MAKE SURE IT IS LINEAR

does constructive interference and destructive interference form a bond?

• constructive does, destructive doesnt

what MOs interact to create bonds

• HOMO and LUMO

molecular orbital vs valence bond (definition, electron location)

• MO theory: when two atomic orbitals combine to make MOs that extend across the whole molecule

  • electrons are DELOCALIZED

• Valence Bond theory

  • when bonds form from 2 atomic orbitals overlapping

  • electrons are LOCALIZED

carbons normal electron configuration doesn’t show how it can make four bonds and even after exciting it it is like that so then you have to hybridize

when drawing the pi bonds make it have one electron

bond angle for a tetrahedral

• 0 lone pairs: 109.5

• 1 lone pair: 107

• 2 lone pairs: 105

difference between electron and molecular geometry

• molecular geometry ignores the lone pairs

dipole moment equation

• charge x distance

• have to conver tfrom esu to d

how to find out how ionic a bond is

• take the actual mean and divide it by the mean that represents the full separation of charges

  • to find the mean for the full separation of charges do charge x distance (and convert to D)

what does a double bond mean in relation to orientation

• the atoms cant move or rotate around it

define protic and aprotic

• protic = when solvents are able to engage in hydrogen bonding

• aprotic = when not able to do hydrogen bonding

  • but can still have polar substances

sigma bonds occur on the bond axis but pi bonds dont

lone pairs go into hybridized orbitals unless there is resonance and they go into unhybridized ones

• why you have to have sp2 or below, need that p open

5 patterns of resonance

1. allylic lone pair

2. allylic positive charge

3. atoms of differing electronegativity

4. lone pair next to a positve charge

5. around the ring

vinylic vs allylic position

• vinlyic is ON the double bond

• allylic is on one bond away from the double bond

What is allylic and vinyllic for

• ONLY for CARBON DOUBLE BONDS

conjugated

• pi bonds split by a sigma bond

allylic lone pair

• 2 arrows

  • first is from lone pair to pi bond, second is from pi bond to lone pair

  • one gets positively charged another negatively

allylic positive charge

• one curved arrow

• take a pi bond and form a new pi bond

• switch where the positive is

lone pair adjacent to positive charge

• move lone pair to the positive charge

pi bond between 2 atoms of differing EN

• give the more EN one the lone pair

most important to least for resonance signficiance

1. filled octets

2. fewer formal charges

3. negative charge on more EN atom and positive on less EN

IF IN RESONANCE THE HYBRIDIZATION HAS TO BE SP2 OR LOWER

• if there is a p orbital already being used then you can’t delocalize an electron

what types of orbitals form single, double, and triple bonds

• hybrid orbitals make single bonds

• double and triple bonds are made from unhybridized p orbitals

out of the ways to represent a molecule, which one doesn’t give information about its structure

• molecular formula

difference between partially condensed structure and condensed

how to draw hydrogens when there is a bond line structure

bicyclic wedge dash notation

resonance structures COEXIST and dont jump from one to another

what do you always do first when assesing resonance

OCTETSSS

avoid drawing resonance structures where the carbons have two different charges

• one carbon has a positive one and then another has a negative one

electrons that don’t move during resonance are LOCALIZED

trigonal pyramidal is not planar

if there is a pi bond and a lone pair they both CANT participate in resonance

if same number of atoms and looks the same

• SAME compound

bronsted lowry definition of acid and base

• acid donates a proton

• bases accept a proton

lewis acid and base definition

• lewis acid accepts and shares electrons

• lewis base donates and shares electrons

bronsted lowry bases and acids are always lewis bases and acids but lewis bases and acids aren’t always bronsted lowry bases and acids

resonance structures are hypothetical

what is the way we quantatively assess strength

• pka

what is the Ka equation

K_a= [H3O⁺] [A^-]

———————-

[HA]

strong acids have weak conjugate bases

you want equilibrium to move to the WEAKER acid and base

when it is a huge difference in pka’s then it is a straight arrow and it isn’t equilibrium ones anymore

how do we qualitatively analyze acidity

• by looking at conjugate bases

• ARIO

when going down the column and then going across a row on the periodic table what is more imporant

• row = electronegativity

  • left to right = increase in EN = more stable = weaker

• column = size

  • bigger size = more stable conjugate base = weaker

for induction it refers to atoms that are not immediately involved in the lone pairs

describe the O in ARIO

• the closer the electrons are held to the nucleus the more stable they are

  • the smaller the atomic orbital the more stable and then the weaker the base the stronger the acid

what is the EXCEPTION in Orgo

• EVEN THOUGH THE NH3 SHOULD BE MORE ACIDIC IT ISNT

• pka’s just prove they don’t work

why is equilibrium shifted to the weaker base

• this is because it is MORE stable and you are always shifting to the most stable state

what do we compare when trying to determine equilibrum

• base and conjugate base

when will an acid/base not be strong enough to depronante

• when its creating something that is less stable

leveling effect

• you have to choose the solvent that won’t react with your reaction

• dont want something to make everything equally strong

  • but need something that can effectively deprotonate/protonate

what acids and bases can we not overcome

• we can’t have an acid stronger then H3O+ be used in water

• we can’t have a base stronger than OH- used in water

• this is because it would always be making H3O+ and OH-

  • because water will always be taking or removing that hydrogen

if a molecule is more branched or less branched will it be more soluable

• less branched because that means it can better surround it

  • because its smaller

bases need what and acids need what

• bases need a lone pair and acids need an H

counterions

• always there because they balance the charge

• just dont include sometimes

CHECK if a proton is being donated/accepted because itf not it is a LEWIS ACID or BASE and not bronsted

if there are carbons in a conjugated pi system the carbons will alternate between partially positive and partially negative

if ka is greater than one what is favored and when ka is less than one what is favored

• greater than one = products

• less than one = reactants