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chemistry p4 topics to stress on

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NOTE : this is surely not a leak, but just the topics to be stressed upon. kindly note that prepare your best, it's just an effort to bring an attention to these possible topics


1. Born Haber Cycle
a. know about definitions
b. know about why lattice enthalpy and electron affinity is negative,
c. know how to draw and identify steps in born haber cycle

2. Electrochemistry
a. calculating E*
b. hydrogen/fuel cell or lead acid battery
c. Faraday's calculations

3. Equilibria
a. buffer solutions
b.acid/base graphs

4.Reaction kinetics
a. Catalysis
b.rate equations

5. Group 2/4
a. thermal stabilities of nitrates (explanations)
b. reactivity compared to Calcium
c. variation of stability of +2 and +4 oxidation states

6. Transition elements
a. ligand exchange
b. how are coloured complexes formed

.... relative strengths of benzene carboxylic acid/chloro acids in terms of inductive effect

.... mechanism of Diazotisation

..... regular organic

Applications.
a. Enzymes
b.role of Fe in haemoglobin
c.isoelectric points of amino acids (zwitterons)
d. NMR
e. Calculation of partition coefficient (single+various extractions)
f. PCB's
g. Polymers (may be showing reaction/repeat units)
h. Ozone
 
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thanks dude...what should be learned from PCB's ...the application booklet has this topic very unclear..i couldnt get it
 
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partition coefficient is in the applications part,
you should know what it means, and calculating Kpc

Kpc is when a solute is added to 2 immiscible solvents in contact with each other, and when the solute partitions itself between the 2 layers

Kpc = [solute in solvent]/[solute in water]
it has no units as it is a ratio
 
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diwash said:
thanks dude...what should be learned from PCB's ...the application booklet has this topic very unclear..i couldnt get it

its uses and its associated hazards
 
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is that much only need for the PCB's and Dioxims.....and what about biomarkers
 
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bionology said:
partition coefficient is in the applications part,
you should know what it means, and calculating Kpc

Kpc is when a solute is added to 2 immiscible solvents in contact with each other, and when the solute partitions itself between the 2 layers

Kpc = [solute in solvent]/[solute in water]
it has no units as it is a ratio

Thnks dude........helped me a lot.. :D
BTW how much r u sure that this topics will be asked.............
 
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i already noted that do not rely on them merely, this is just what I worked out seeing the recent past papers and syllabus outline
 
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PCB's are poly-chlorinated by-phenyls
properties :
1. chemically stable/high resistance to heat
2. low flammability
3. have dielectric constant


Uses:
1.hydraulics system
2. lubricating oils
3. used in capacitors/circuit breakers

toxicity:
1. Carcinogens
2. when inhaled by mother/ slow fetish development


environmental concerns :
1. nonbiodegradables/ persists in the atmosphere due to many cl's present
2. Fat soluble/ builds up in the animal's body
 
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Electricity conducting plastics:
-The molecule has alternating single and double bonds resulting in s conjugated system
-The system can have cis or trans configuration
-Technically conducting polymers are semi-conductors as they have to be doped in order to make them conductors
-Conjugated hydrocarbon polymers can emit light
 
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Nanotechnology:

Nanomaterials fall into two categories:
a. Fullerenes
b. Inorganic nanoparticles

A. Fullerene
-Any molecule composed entirely of carbon in the form of a hollow sphere, elllipsoid or tube
- Spherical fullerene called Buckyball
- Cylindrical nanotube called buckytube

Fullerenes are similar in structure to graphite, which is composed of stacked graphene sheets of linked hexagonal rings; but they may also contain pentagonal or hexagonal rings
Suffix "-ene" shows that some C atoms are covalently bonded to three others


Buckminsterfullerene:
-Smallest fullerene molecule in which no two pentagons share an edge
-Van Der Waals diameter of a C60 molecule in 1.1nm

Properties:
-Carbons are sp2 and sp3 hybridised
- Being perfectly round, quite resistant to high speed collisions
-Buckyballs twice as hards as diamond when compressed
-Internal spacces can be used to trap rective atoms and literally act as molecular cage
Properties of bucky crystals(more important)
-Pure balls in the crystal make it an Insulator. If the balls doped, the crystal becomes a conductor and thus acts as a semiconductor.
-Soluble in some solvents and conditions ( soluble lin methylbenzene, insoluble in water). Van der waals' forces between water and buckyballs wouldn't be energetically feasible
-More slippery than teflon as the balls can be considered as ball bearings. Also due to the fact that only weak van der waals' forces holding the bucky balls in the crystal
-Due to internal spaces in balls, the crystal has low density
-The crystal is soft as there are weak bonds between balls
-Low melting point as weak van der waals' forces holds the crystal together


Carbon Nanotubes:
-Fullerenes with cylindrical nanostructure
- Dimater: few nanometers

Properties:

Strength:
-Very strong in the axial direction under tension but low in lateral direction
-Withstand a pressure of 24GPa without deformation

Kinetic:
-In multi-walled nanotube, inner core may slide over outer almost without friction

Electrical:
-Conductivity very high in axial direction as all the C atoms are sp2 hybridised

Nanoscale test tubes:All particles collide in a very small space and collision frequency is very high giving a high yield
 
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