S3.2 Organic Chemsitry Flashcards
saturated
functional group
all single bonds
What happens to bp as more carbons are added to a chain
- more electrons added
- stronger LDF
- higher bp
Structural Isomerism
Compounds with the same molecular formula but different structural arrangements.
Functional group isomerism
Same molecular formula but differet functional groups
Stereoisomerism
Compounds with the same structural formula but a different spatial arrangement of atoms.
clasifying H domains
look at what carbon IS DIRECTLY bonded to
* only include the carbon as a domain IF it is bonded to a hydrogen
when asked to compare HNMR spectra mention…
- amount of peaks
- amount of unique environments
what does the base ion/molecular parent M+ peak tell you in mass spec
the molecular mass of the compound
fingerprint region
the region of a infrared spectrum below 1500cm-1, ehich shows the exact match tp spectrum of a known compound- (e.g primary, secondary, halogeno-,)
Periodicity
repeating pattern of chemical or physical properties
why esters do not interact with water
- water has strong hydrogen bonds
- esters have comparably weaker dipole-dipole moments & LDF’s
- it is less energetically favorable for water to break its H-bonds to interact with the ester (to form hydrogen bonds w it)
interpeting peaks on HNMR
- tells you adjacent h atoms
- uses n+1 rule for peaks (singlet, doiblet, triplet, qiartet)
- peaks shpw unqie H environments
- if H’s are equivalent (like mirrored on both sides for example) the peaks are only counted ONCE!
what does integration curve/trace on HNMR tell you
H atom ratio to each environment
why does HNMr work
- y-axis = absorbance, x-axis = ppm (parts per million)
- based on shift of tetramethylsaline
- protons aligned with magnetic field exposed to Radio frequency signal
- protons flip from lower to higher
- radio signal switched off => return to low
- aligned protens re-emit freuqnency absorbed _> detected by HNMR
(energy splits betwene aligned & against aligned protons=> unaligned higher in energy)
identifying chiral molecules
- bonded to 4 UNIQUE groups
- have to be isomers in terms of plane orientation (one front, one back)
=> rotate plane polarised light in opposite direction
=> if not chiral = NO EFFECT on plane polarised light
reading mass spectrum
- y-axis = relative intensity; x-axis = m/z ratio
- peak furtherst to right is bass eion peka (shows full Mr of compounds)
- each peaks gives syou the mast after MASS WAS LOST
- to find lost Mr of fragment (base ion peak- fragment peak = mass of fragment lost)
=> use data booklet
enantiomers
optical isomers which are non-superimposable
optically active
contain chiral centre and rotate plane polarised light
cis-trans isomerism
isomers due to restricted rotation around a double bond or ring structure (due to pi bond)
degrees of carbon copounds (1er, 2er, 3er)
- 1er= carbon is attached to a single other carbon
- 2er = carbon is attached to 2 other carbons
- 3er = carbon is attached to 3 other carbons (cannot be further oxidised)
addition reaction
adding to identical alkenes = double bond gets broken = long chain
addition of bromine
- double bond breaks, bromine adds
- from yellow to colorless
- delcolorises bromine water
how does IR work
- bond exposed to IR of same freuqnecy as bond vibration
*bond svibrate; symmetrically, asymmetrically, bending - y-axis= transmittance
- x-axis= wavneumber (1/wavelength)
