4.1 Flashcards
Saturated vs unsaturated
Saturated = no double bonds
Unsaturated = double bonds
What’s a homologous series?
?
Empirical formula = ?
Simplest whole number ratio of atoms of each element in a molecule
Naming compounds
OH = alcohol
COH = aldehyde
CO = ketone
COOH = carboxylic acid (-oic acid)
definition of STRUCTURAL ISOMERISM
Compounds with the SAME MOLECULAR formula but DIFF STRUCTURAL formula
Homolytic fission = ?
Each bonded atom takes ONE of the shared pair of electrons
Radicals formed
Heterolytic fission = ?
One bonded atom takes BOTH of the shared pair of electrons
-ve and +ve ions formed
Alkanes
CnH2n+2
SATURATED - covalent sigma bond
TETRAHEDRAL - 109.5 degrees
Additional carbons = increased bpt (higher SA, stronger London forces)
Increased branching = less SA contact, weaker London forces (don’t pack together)
Alkanes; combustion
X + excess O2 -> CO2 + H2O
Alkanes; + UV light
e.g. CH4 + Br2 -> CH3Br + HBr
Substitution (from monosubstituted isomers)
Alkanes; free radical substitution
e.g. Brominisation
1 INITIATION
Br2 -> 2Br• (+UV light)
2 PROPAGATION
i) CH4 + Br• -> CH3• + HBr
ii) CH3• + Br2 -> CH3Br + Br•
3 TERMINATION
2Br• -> Br2
2CH3• -> C2H6
CH3• + Br• -> CH3Br
Alkanes
CnH2n
UNSATURATED - 3e- in sigma, one in pi bond
TRIGONAL PLANAR - 120 degrees
Pi bond will break
definition of STERIOISOMERISM?
SAME STRUCTURAL formula but DIFF ARRANGEMENT of atoms in space
E/Z isomerism = ?
C=C double bond
Diff. groups attached to each C
E = diff sides Z = same side
(Top/bottom)
Cis/trans isomerism = ?
C=C double bond
Each attached to diff. groups
One group must be HYDROGEN
Cis = same side Trans = diff side
Cahn-Ingold-Prelog
nomenclature = ?
Z = groups of HIGHER PRIORITY on same side E = groups of HIGHER PRIORITY on diff sides
HIGHER ATOMIC NO = HIGHER PRIORITY
(Group w higher atomic no. at first point of difference = higher priority)
Alkenes; addition
Hydrogen+nickel catalyst=alkane
Steam+phosphoric acid catalyst=alcohol
Halogens=haloalkanes
Alkenes; electrophilic addition
i) high electron density attracts ELECTROPHILES
Electrophile = e- pair acceptor
ii) e- pair on pi bond attracted to electrophile (dipole could be induced by high electron density)
iii) carbocation formed
Br s- becomes Br- and is attracted to carbocation
Markownikoff’s Rule = ?
When a hydrogen halide reacts with an unsymmetrical alkene, the hydrogen attaches itself to the C with the greater number of H atoms already attached
Carbocation stability
Major produce formed via most stable carbocation
Less H = more stable
Primary-secondary-tertiary
Alkenes; polymerisation
High temp and high pressure and catalyst
Addition polymerisation: from long saturated chains
Polymerisation; disposing of waste polymers
Lack of reactivity = non-biodegradable = build up = kill marine life
Polymerisation; recycling
Decreases landfill
Have to be sorted
Used to make new products
Polymerisation; PVC recycling
Hazardous = high Cl content Burnt = releases hydrogen chlorine = corrosive
Solvents could dissolve the polymer
