Quick Summary of Study Design

[bar0029]

So it's 8 a.m and I can't go back to sleep because all I can think about is CHEMISTRY!!
and as a result, I thought it would be appropriate to just summarise the study guide for you, in a really brief quick way 

ANALYTICAL CHEM

1. volumetric analysis: simple and back titrations, acid-base and redox titrations

Volumetric analysis is the process of titrating a solution with an accurately known concentration (standard solution) with a known volume of a solution with an unknown concentration, in order to determine this unknown concentration. 

Simple titrations: generally acid vs base and redox
need to have a suitable indicator whose colour will change a few drops after the equivalence point
familiarity with strong/ weak acids and bases will aid in choosing the correct pH curve alongside the appropriate indicator
NOTE that an indicator is in actual fact a weak acid whose conjugate base is of different colour 
require a standard solution *accurately known concentration* which can be obtained by using a primary standard *a substance that is so pure that it's no. of mole can be directly determined from it's mass* or by a standardised solution *whose concentration has been determined by volumetric analysis/ titration*

Back titrations: used when-
                     (i)   reaction is too slow
                     (ii)  no sharp end-point b/c acid and base are both weak
                     (iii) one of the reactants/ products are volatile
briefly: it involves reacting a substance in excess, and to determine how much has reacted you further titrate it to further determine how much was in excess.
thus, n(reacted) = n(initial) - n(in excess)
don't add indicator until second reaction as this is the titration

2.  gravimetric analysis

this is analysis by mass which involves forming, drying and weighing a precipitate which enables us through calculations to determine the no. of mole and further calculations in the original sample under analysis

- blend and filter your sample
- add suitable precipitating reagent in excess
- wash with distilled water in order to remove any soluble impurities
- dry ppt. in an oven above 100 degrees, to evaporate any water
- weigh the ppt.
- repeat last two steps until constant mass is achieved 

3. calculations including amount of solids, liquids and gases; concentration; volume, pressure and
temperature of gases

n= mass/ Mr
C x V = n
pV = nRT ---> always convert T into kelvins, p into kPa and V into litres
n = no. of particles / avagadro's no.
DILUTIONS ONLY: C1 x V1 = C2 x V2


4.  use of oxidation numbers to write redox equations

oxidation numbers allow us to determine whether a species is acting as a reductant *loses e-* or oxidant *gains e-* in a reaction
- O.N of element = 0
- O.N of mono-atomic ion = charge on ion e.g. Fe3+
- O.N of poly-atomic = make it equal to overall charge e.g. MnO4-
- O.N of neutral = make it equal to zero e.g. NaCl
- O.N of oxygen = -2 except if bonded to fluorine or in peroxide
- O.N of hydrogen = +1 unless in a hydride e.g. LiH, O.N = -1

always balance redox equations with electrons!


5.  principles and applications of chromatographic techniques and interpretation of qualitative and
quantitative data from thin layer chromatography (TLC), high performance liquid chromatography
(HPLC) and gas chromatography (GC)

Chromatography is the analytical technique of separating components of a sample and is based on two main principles:
that each substance will have a varying degree of adsorption*stick* onto the stationary phase *still phase* and a varying degree of desorption*unstick* back into the mobile phase *moving phase*
   Every chromatographic technique has a mobile and stationary phase

(i) Thin layer chromatography:
used for dyes and generally amino acids
Qualitative
stationary phase: glass plate/ plastic/ or aluminium foil coated with a layer of silica gel or alumina
mobile phase: any suitable solvent

(ii) high performance liquid chromatography:
used for non-volatile substances with Mr > 300
Qualitative and quantitative
stationary phase: glass beads in column with high S.A coated with silica gel or alumina
mobile phase: suitable solvent

for quantitative analysis, a calibration curve must first be achieved. this involves running through a number of samples with known concentrations under identical conditions ALWAYS and forming a linear relationship whereby the area under the peak is directly proportional to the concentration of each component.

(iii) gas chromatography:
used for volatile substances whose Mr < 300
Qualitative and quantitative
stationary phase in GLC: column coated with high boiling point ester or hydrocarbon
stationary phase in GSC: column coated with alumina or silica gel
mobile phase in GLC and GSC: an inert carrier gas that sweeps the components

for quantitative analysis, a calibration curve must first be achieved. this involves running through a number of samples with known concentrations under identical conditions ALWAYS and forming a linear relationship whereby the area under the peak is directly proportional to the concentration of each component.

6.   principles and applications of spectroscopic techniques and interpretation of qualitative and
quantitative data from atomic absorption spectroscopy (AAS), infrared spectroscopy (IR), mass
spectroscopy, nuclear magnetic resonance spectroscopy (NMR), and visible and ultraviolet
spectroscopy (visible-UV)

Spectroscopy is based on the fact that different regions of the electromagnetic spectrum will affect atoms or molecules at varying degrees and allows us to obtain different information

AAS: conc. of metals and metal ions
uses hollow cathode lamp that excites electrons
qual and quant

IR: types of bonding and functional groups
uses infra red light that causes molecules to change vibrational energy levels resulting in stretching and bending of intramolecular bonds
qual

NMR: the complex structure of organics by telling us the different chemical environments of mainly H and C
radio waves causes change in the spinning of nucleons causing them to flip
qual

UV- vis: conc. of colourless organics
uv- visible range of light excites e- and transmittance is measured to account for absorbance
i.e. absorbance = initial - transmittance
qual and quant

mass spec: gives info. on the molecular mass, the different fragmentations and relative isotopic abundance
doesn't require absorption of energy
vaporisation, ionisation, acceleration, deflection and detection
qual.


tbc.

[bar0029]

ORGANIC CHEM

1.  structure and systematic nomenclature of alkanes, alkenes, amines, chloroalkanes, alkanols and
carboxylic acids up to C10
meth:  1
eth:    2
prop:  3
but:   4
pent:  5
hex:   6
hept:  7
oct:   8
non:  9
dec: 10

alkane: -ane
alkene: -ene
alkanol: -ol
carboxylic acid: -oic acid
amines: -amine or amino-
chloroalkanes: chloro-

2. common reactions of organic compounds: addition reactions of alkenes, substitution reactions of
alkanes and primary chloroalkanes, oxidation of primary alkanols, esterification

Alkanes:
these are very unreactive due to the fact that they are saturated *have all carbon to carbon single covalent bonds*
only undergo substitution and combustion reactions
substitution: involves reacting with an atom or functional group and replacing one or more hydrogen atoms. usually requires a catalyst, e.g. in halogenation reactions, UV light is required to form chlorine free radicals
combustion: involves react in excess oxygen to produce water and carbon dioxide. in incomplete combustion, oxygen is the limiting reagent and carbon monoxide and water is produced

Alkenes:
more reactive than alkanes due to their degree unsaturation  i.e. due to their carbon to carbon double covalent bond(s). can react in addition reactions.
addition: adding a atom or functional group across the double bond to produce a single product 
IF ONLY ONE PRODUCT PRODUCED, THIS IS INDICATIVE OF AN ADDITION REACTION
note that although benze has C=C bonds, it doesn't undergo addition reactions but instead substitution reactions

Chloroalkanes:
primary chloroalkanes *have chlorine on a terminal carbon* can undergo substitution reactions readily, due the electronegative nature of the chlorine atom
--> reaction with NaOH or KOH or OH-
the hydroxyl -OH will replace the chlorine to produce a primary alkanol

Alkanols:
primary alkanols *have the hydroxyl on a terminal carbon* can undergo oxidation, condensation and substitution reactions.
oxidation:
the oxidation of a primary alkanol will produce an intermediate aldehyde that will then be further oxidised to produce a carboxylic acid. the oxidation of a secondary alkanol will produce a ketone and no carboxylic acid.
condensation:
because of the nature of the hydroxyl, alkanols can undergoe condensation reactions including formation of esters, polyester and ether linkages
substituion:
the hydroxyl may be replaced by one or more atoms.
e.g. reacting with ammonia NH3 to produce an amine

Esterification:
condensation reaction between a carboxylic acid and an alkanol
prime example: the formation of biodiesel and lipids


3.  principles of fractional distillation

Separation of usually large hydrocarbons on a physical basis, based on their boiling points
it involves a fractionating column, whereby the top of the column is cooler than the bottom
it's a continuous process of evaporation and condensation
As you move you down the column, the physical properties of the molecules are:
- inc. in boiling point
- inc. in size, mr, surface area and therefore, inc. in no. of dispersion forces
- inc. in viscosity
- dec. in volatility and flammability

following fractional distillation is usually cracking, such that long alkanes are broken down into saturated and unsaturated organic molecules that have a far greater use


4.  primary, secondary and tertiary structure of proteins and the function of protein catalysts
(enzymes)

proteins are one of the biological polymers made from the condensation polymerisation of amino acids
the amino acids are referred to as 2- amino acids b/c the carboxyl, amine and residual groups are all attached to the same central carbon
in the condensation reaction, the amine group reacts with the carboxyl to produce an amide functional group -CONH-

*primary structure:
the no. of and sequence of the amino acids in a polypeptide
e.g. Ala-Gly-Ser-Phe

*secondary structure:
intermolecular interactions between different parts of the chain forming hydrogen bonds resulting in coiling and folding of the chain
e.g. alpha helix and beta pleated sheet

*tertiary structure:
various interactions between the residual groups of the polypeptide. such interactions include:
- ionic attractions
- ion-dipole
- dipole-dipole
- dispersion
- hydrogen bonds
- covalent: disulphide bridges between cysteine and cysteine

because structure is directly linked to function, the three-dimensional structure determined by the above, will in turn determine the fuinction.
one particular function is the enzyme. enzymes are proteins that act as biological catalyst by increasing the rate of reaction in biological systems by decreasing the activation energy required for a reaction to occur.
they have an active site (determined by tertiary) binds to the substrate forming a enzyme- substrate complex that will form more or one products
the enzyme-substrate complex is held by many different intermolecular attractions



5.  biochemical fuels including fermentation of sugars to produce ethanol

biochemical fuels are those that have been derived from naturally occurring biological matter
these include, biogas, biodiesel and bioethanol

biogas: main component is methane and carbon dioxide
biodiesel: main component methylesters, and is a transesterification reaction 
bioethanol: main component ethanol produced from anaerobic fermantation of glucose in the presence of yeast enzymes


6.  the structure and bonding of DNA and its applications in forensic analysis

DNA made from three components:
- nitrogeneous base: Adenine, thymine guanine and cytosine
adenine and guanine are the purines and cytosine and thymine are the pyrmidines
- deoxyribose sugar
- phophate group- which gives dna it's overall negative charge

C1: where the nitrogeneous base is bonded
C3: where the hydroxyl is and where the sugar phosphate backbone occurs (bonds to)
C5: where the phosphate group bonds to

primary structure:
the sequence of the different nucleotides (A, G, T or C) joined by the phosphodiester back bone

secondary structure:
the hydrogen bonding between complimentary base pairs in accordance to the complimentary base pairing rule where A bonds to T with 2 bonds and G bonds to C with three bonds
*thus a G-C count is an indication of the melting temperature of the DNA strand*

tertiary structure:
ion-dipole interactions between histones (proteins made from positively charged amino acids) and the negatively charged dna (due to phosphate) forming the chromosome structure


DNA FORENSIC ANALYSIS
dna can used for forensic analysis by making a dna fingerprint and comparing these to a dna fingerprint of a suspect. it just provides an indication and is not used for absolute proof in the legal systems

if we have a sample of biological tissue or fluid e.g. blood, saliva or semen we can use this to make a dna fingerprint by:
1. isolating the sample (through centrifuge)
2. amplify the sample using polymerase chain reaction
3. cut specific regions of the dna using restriction enzymes/ endonucleases
4. subject to electrophoresis separating the dna by mass
5. blot onto a nitrocellulose paper
6. label with radioactive or fluorescent probes
7. view under appropriate wavelength e.g. uv



7.  use of proteins as markers for disease
the absense/ presence of a protein at varying concentrations is an indication of a disease in the body
it can be used to:
- determine how severe the disease is
- whether treatment is working
etc.



8. function of organic molecules in the design and synthesis of medicines including the production
of aspirin from salicylic acid.

altering the structure of organic molecules to be better suited drugs on the basis of the active site of the substrate is called rational drug design
a prime example of rational drug design is asprin and paracetemol

asprin is made from the esterification reaction between:
1. ethanoic acid: (condensation reaction) low yield because water drives the backwards hydrolysis reaction
2. acetic anhydride: high yield because it is a one way reaction where ethanoic acid that is produced cannot drive the backwards reaction
asprin has been altered because the active ingredient salicylic acid is an irritating substance to the lining of the digestive tract.
in alkaline conditions e.g. the small intestine, the hydrolysis of asprin occurs

paracetemol is made from the esterification reaction between 4-amino-phenol and usually ethanoic acid










goodluck for the exam  :smitten:

[bar0029]

i may have left out lipids and carbs :\ sorry.

[azure]

thanks!   good luck for the exam