5 bonding patterns in which resonance occurs
- Allylic lone pairs
- Allylic positive charge
- Lone pair of electrons adjacent to a positive charge
- A pi bond between two atoms with differenct electronegativities
- Conjugated pi ponds in a ring
directly bonded to a C=C double bond
Bonded one atom away from a C=C double bond
A very stabilizing force in which electrons are in resonance
Bronsted-Lowry definition of acid/base reactions
- Acids donate a proton
- Bases accept a proton
Results in a net increase in the number of C-H bonds, or a net decrease in the number of C-O bonds or equivalent
Results in a net decrease in number of C-H bonds or a net increase in the number of C-O bonds or equivalent
What leads to a carboxylic acid?
Addition of a molecule of water to the aldehyde followed by a second oxidation
Homolytic bond cleavage
Both atoms break equally and leave with the same number of electrons
Heterolytic bond cleavage
One atom breaks off with a larger portion of electrons creating ions of both atoms.
A (-) sign for ΔG tells us...
A process is product favored (spontaneous)
A lower Energy of Activation results in...
A greater reaction rate
Where do transition states occur?
An an energy maxima. (peaks on a graph)
Where do intermediates occur?
At an energy minima. (low points between peaks)
A catalyst can provide a more favorable pathway for an organic reaction by...
- Increasing the susceptibility of an electrophile to nucleophilic attack
- Increasing the reactivity of a nucleophile
- Increasing the leaving ability of a group by converting it to a weaker base
- Increasing the stability of a transition state
What is the order of operations in a Mass Spectrometer?
- Sample introduction
- Mass Analysis
- Ion detection/data analysis
Electrospray ionization: takes sample, mixes with a liquid, and sprays solution (which is highly charged) causing the molecules to fragment until its a 1+ charge
Electron Impact: putting a molecule in front of a filliment and shooting electrons at it in an attempt to change its charge
Matrix assisted laser disorption ionization: shoots powerful laser at sample which is partially protected by the matrix which absorbs some of the energy. This changes the charge of the molecule
Ion separation (analyzer)
Quadruple mass spectrometer design. Shoots ions through a tube and allows them to be analyzed. Ions cannot touch sides of tube.
Nominal molecular mass
the molecular mass to the nearest whole number
The peak with the largest m/z value represents...
the molecular ion (M)
What are fragment ion peaks?
Peaks with smaller m/z values, represent positively charged fragments of the molecule
The more stable a fragment...
The more that will be observed in the mass spectrum
Fragmentation behavior of Alkyl, Halides, Ethers, and Alcohols
- A bond between carbon and a more electronegative atom breaks heterolytically
- A bond between carbon and an atom of similar electronegativity breaks homolytically
- The bonds most likely to break are the weakest bonds and those that lead to formation of the most stable cation
What kind of frequencies, wavenumbers, and wavelengths are associated with high energy?
- High frequencies
- Large wavenumbers
- Short wavelengths
Types of bending vibrations in IR
- Scissor: inward towards central atom
- Rock: two branched atoms are pulled in one direction
- Twist: two branched atoms twist in opposite directions
- Wag: two branched atoms twist in same direction
When a bond stretches...
The increasing distance between atoms increases the dipole moment