[NCIShippo]

.

If you're sitting this exam on June 3rd 2009, then good luck! I thought this would be a good way to get some revision questions/topics sorted.


Topics:


Module 1 - Basic Concepts and Hydrocarbons

Naming basic hydrocarbons
Identifying functional groups
Organic formulae
Structural and Skeletal formulae
Isomers
Hydrocarbons and Crude Oil
Hydrocarbons of fuels
Alkanes
Alkenes
Polymers
Substitution and Addition Reactions


Module 2 - Alcohols, Halogenoalkanes and Analysis

Formulae of alcohols
Properties of alcohols
Halogenoalkanes
Percentage Yield & Atom Economy
Infrared Spectrometry
Mass Spectrometry
Mechanisms


Module 3 - Energy

Exothermic & Endothermic reactions
Enthalpy profile diagrams
Bond energies (all required data is in data booklet)
Rates of reaction
Catalysts
Equilibrium


Module 4 - Resources

The Greenhouse Effect
The Ozone Layer
Green Chemistry (recycling)



Hope that is useful. The paper (of length 1 hr 45 mins) is on the 3rd June 2009, in the morning. Also, if you are taking Unit 1 - Atoms, Bonds and Groups (F321), then this paper will be directly after it (it will be a long morning ).

The Specimen Paper and Mark Scheme is available on the OCR website, so enjoy.

Good luck to everyone!


NCIShippo




Peoples revision notes:

Spoiler:

Just revised halogenation of alkanes:

When alkanes react with a halogen.

E.g:

C2H4 + Cl2 >>> C2H5CL + HCl

Radical substitution:
- Covalent bond broken by homolytic fission forming 2 radicals.
- Hydrogen atom substituted by Halogen atom.

Radical - species with an unpaired electron.

Mechanism: Free Radical Substitution Reaction

Initiation
UV
Cl2 >>> .2CL

Bond broken by homolytic fission, forming 2 Cl radicals.

Propagation
1) .Cl2 + C2H6 >>> .C2H5 + HCl
Cl radical attacks alkane molecule

2) .C2H5 + Cl2 >>> C2H5CL + .Cl
New alkane radical molecule attacks another Cl molecule.

Continues until no reactants remain.

Propagation

.C2H5 + .C2H5 >>> C4H10
.C2H5 + .Cl >>> C2H5Cl

Two radicals join together to form a stable molecule.

Limitations of radical substitution

Further substitution - produces mixture of products.
Radical exposures causes - premature ageing
- chronic illnesses
Antioxidants - used to check body for radicals.

Spoiler:

Revision - when combining monomers to form a polymer, rearrange so that the double bond is in the middle, and so that any other groups are above or below the pi-bonded carbons. When naming the polymer, just put: poly(and the monomers name in brackets)!

Spoiler:

Electrophilic Addition Alkene + HBr -------> Halogenoalkane
Nucleophilic Substitution Halogenoalkane -------> Alcohol
Free Radical Substitution Alkane + Chlorine ----------> Chloroalkane
Elimination Alcohol + H2SO4 ------------> Alkene
Oxidation Primary Alcohol + K2Cr2O7 + H2SO4 ---------> Aldehyde or Carboxylic Acid

Spoiler:

Hydration:
High temp (300*c), high pressure (60 atm), phosphoric acid catalyst
Ethene + Steam --> Ethanol

(Di)Halogenation:
RTP, example of electrophilic addition
Ethene + Bromine --> 1,2-dibromoethane
(need to know mechanism)

Addition of a hydrogen Halide:
RTP, example of elecrophilic addition
Ethene + Hydrogen Bromide --> 1-bromoethane
(need to know mechanism (very similar to one above))

Hydrogenation:
150*c, (rainey) nickel catalyst
Ethene + Hydrogen --> Ethane

Alcohols:

Combustion of an alcohol:
CnH2n+1+(1.5n)O2 --> nCO2 + (n+1)H2O

Making Ethanol:
Hydration of ethene:
Phosphoric acid catalyst, 300*C, 60 atm
Ethen + Steam --> Ethanol

Fermentation
Zymase (enzyme in yeast), 37*c
Glucose --> Ethanol + Carbon dioxide

Oxidation of alcohols:
Sulphuric acid, potassium dichromate (acidified)
Primary alcohol:
e.g. propan-1-ol

Distillation:
Propan-1-ol + [O] --> Propanal (aldehyde)

Reflux:
Propan-1-ol + 2[O] --> Propanoic acid (carboxylic acid)

Secondary alcohol:
e.g. butan-2-ol

Butan-2-ol + [O] --> Butanone (keytone)

Tertiary alcohols do not oxidise

Dehydration of an alcohol:
Elimination reaction
Sulphuric acid/phosphoric acid, heat, reflux for 40 mins
e.g. ethanol

Ethanol --> Ethene + water

Formation of an alcohol by hydrolysis of a halogenoalkane:
Nucleophilic substitution
Reflux
Hot hydroxide ions (aqueous sodium hydroxide commonly used)
e.g.
1-chloropropane --> propan-1-ol
(need to know mechanism)

Spoiler:

I'll go over the whole module, just for ease.

2.4.1 The Greenhouse Effect - Global Warming

Greenhouse gasses are necessary
The Earth receives most of its energy from the sun
Most of this energy is absorbed, but some is reflected out of the atmosphere
Greenhouse gasses can stop this energy being reflected out of the atmosphere and it is reflected back (again) to the Earth
This results in the planet 'warming up'
When greenhouse gasses absorb infrared radiation, the vibrate
The greenhouse effect of a gas does not only depend on its concentration in the atmosphere, but also on its ability to absorb IR radiation
Gasses have a 'global warming potential' (GWP) - this is related to the lifetime of a gas in the atmosphere as well as the ability of the gas to absorb IR radiation
Climate change is caused by coal, natural gas and oil being burnt
Attempts to reduce greenhouse emissions have been made - through examples such as the Kyoto protocol, EU strategy in 2007

Solutions to the greenhouse effect:
Alternative fuels: wind, tidal, solar, nuclear
Carbon capture and storage:
Immediate strategy to get rid of waste CO2
Use underground porous rock (acts as a sponge)
Can also put CO2 into old oil and gas fields

Decarbonised fuels - CH4 + 2H2O --> CO2 + 4H2

The CO2 produced can be piped offshore to an oilfield. Doing this enables easier extraction of the final 30% of oil from an oilfield.
The H2 can be burnt with water as the only byproduct or it can be used in fuel cells
The UK can store a LOT of CO2 - many years

Can store CO2 as carbonates
CaO + CO2 --> CaCO3
However, this is a very slow reactions, increasing the rate is very energy intensive. A power station using mineral storage would need 60 - 18% more energy than a plant without CCS


The Ozone layer
'Good' and 'bad' ozone depends on where it is:

Bad ozone: Near to the Earth's surface (troposphere), an air pollutant with harmful effects on the respiratory systems of animals
Good ozone: In upper atmosphere (stratosphere) protects living organisms by preventing harmful UV light from reaching the Earth's surface

Ozone layer is found in the stratosphere (10-50 km above Earth's surface)
UV radiation from the sun has wavelengths in the range 270 - 400 nm
The ozone layer filters out wavelengths less than 320 nm
Shorter wavelengths are very damaging to life
Ozone converts UV radiation into heat --> ozone layer is at a higher temperature than other parts of the upper atmosphere

The ozone-oxygen cycle
Ozone is continuously being formed and broken down in the stratosphere
There are 3 types of ozone - UV-a (320 - 400nm), UV-b (280 - 320nm) and UV-c (200 - 280nm)

Nearly all UV-a reaches the Earth's surface, it has less energy and is nota s damaging
UV-b can cause sunburn and sometimes genetic damage (can result in skin cancer) if exposure is prolonged
UV-c is entirely screened out

Any decrease in the ozone layer would allow more UV-b to reach the Earth's surface --> more damage to organisms

Formation of ozone:
O2 + (radiation < 240 nm) --> 2O
O2 + O --> O3 + heat
Heat is absorbed by air molecules in the stratosphere, raising the temperature

How the ozone layer works:
O3 + (radiation < 310 nm) --> O2 + O
O immediately reacts with other O2 to reform ozone
O2 + O --> O3 + heat
This process repeats

Chemical energy is when O and O2 combine is converted into kinetic energy of molecular motion (heat)
The overall effect is to convert penetrating UV radiation into heat without any net loss of ozone

A steady state is reached, where ozone is being formed at the same rate it is being broken down

O2 + O <--> O3

Removal of ozone:
O3 + O --> 2O2
However, this rate is slow

Ozone depletion:
Ozone Depleation Potential (ODP) --> Relative amount of breakdown to the ozone layer caused by the substance. It is compared with CFCl3 which has an ODP of 1.0

CFCs can be broken down in the stratosphere and become radicals

Initiation:
CFCl3 --> Cl· + ·CFCl2

Propagation:
Cl· + O3 --> ClO· + O2
ClO· + O --> Cl· + O2

Overall: O3 + O --> 2O2

Controlling air pollution:

Combustion engines in cards emit pollutants: carbon monoxide, oxides of nitrogen, unburnt hydrocarbons

CO: Can bind to Haemoglobin and damage tissues
NOx: Can form low-level ozone, can cause acid rain
Unburnt hydrocarbons: React with nitrogen dioxide and form low-level ozone

Catalytic converters
Typically made from platinum, rhodium and palladium on a honeycomb mesh (large surface area)
Harmful gasses are converted into less harmful products
Two types:
Oxidation ctalysts:
Used on diesel engines to decrease emissions of CO and unburnt hydrocarbons, combined witha filter, they also remove particulate matter and nitrogen oxides

Three-way catalyst: Fitted to petrol engines, nitrogen monoxide reacts with CO to form nitrogen and CO2

How the catalyst functions
Provides a surface on which the reaction takes place
CO and NO gas molecules diffuse over the surface, some molecules are held onto the metal surface by ADSORPTION (the process that occurs when a gas, liquid or solute is held to the surface of a solid or, more rarely, a liquid)
Temporary bonds are formed between the catalytic surface and the gas molecules
These bonds hold the gas molecules in the correct position on the metal surface where they react
After the reaction the CO22 and N2 products are desorbed from the surface and diffuse away

I'll do green chemistry in a bit :P

^^Woody. Is an absolute legand!

Spoiler:

http://www.thestudentroom.co.uk/atta...0&d=1243518624

I'll update as more revision notes are posted!

[win2kpro]

Wow, great thanks! We will kick this thread off soon enough after we meet some problems revising hehehe. First ill have to "start" revising

And regarding your question, I sat it in January, and so far it has been the best exam I have done (at A level) . I was amazed by what I got

[Stikki]

Hi NCIShippo. I see you've migrated from the physics thread like me

I'm here to leech knowledge off other students I'm here see what I can do to help other students. Although keep in mind I'm not brilliant at chemistry.

[InquilabZindabad]

Originally Posted by Stikki

I'm here to leech knowledge off other students

I know absolutely zilch about modules 3+4 Time to actually read the textbook.

[BristolBoywonder]

I don't actually think i've even done module 2 and by revising for other subjects I have managed to push the little I knew about chemistry straight out of my head. Should be a fun half term.

Have any of you looked at the old syllabus past papers? Do we need to know all the stuff from the chains, rings and spectroscopy paper they did?

[Stikki]

Originally Posted by BristolBoywonder

I don't actually think i've even done module 2 and by revising for other subjects I have managed to push the little I knew about chemistry straight out of my head. Should be a fun half term.

Have any of you looked at the old syllabus past papers? Do we need to know all the stuff from the chains, rings and spectroscopy paper they did?

No. There are a few questions in some papers that we don't have to know about.

For instance, we did the June 2008 chains and rings paper in class and the part about amines in question 5 we didn't have to know (I think the rest is ok).

It is a bit frustrating if you're going through a past paper and find a question that isn't in the new syllabus, but you assume it is and that you're just an idiot. And then end up wasting your time by searching for it in the textbook.

We could make a list of the questions from each paper we don't have to know. But unfortunately I don't think anyone would have the time to do that now with the chemistry exam so close.

[raj_mostwanted]

guys do you think we could have a question on AMINES in nucleohilic addition

[raj_mostwanted]

guys one more Q pls DESCRIBE HOW YOU WOULD MONITOR THE REACTION RATES IN THE HYDROLYSIS OF CHLOROETHANE, BROMOETHANE AND IODOETHANE

[AnythingButChardonnay]

Chemistry is my worst subject, which is especially distressing given that it is my most important subject, and given the extent to which I ballsed-up physics on Thursday.

I find the various types of addition extremely confusing.

[BristolBoywonder]

did you also do physics g482?
holy crap that was hard, i'm almost certain to be retaking it in january. yeh chemistry is quite difficult all I can recommend is practice it one day then do a practice question the next day to see if you have learnt and go about it like that. If you put in the hours they will pay off.

[cyborg]

Originally Posted by raj_mostwanted

guys one more Q pls DESCRIBE HOW YOU WOULD MONITOR THE REACTION RATES IN THE HYDROLYSIS OF CHLOROETHANE, BROMOETHANE AND IODOETHANE

Add dilute aqueous ethanolic silver nitrate followed by nitric acid. The speed at which the halide precipitates form shows you the relative rates of hydrolysis.

[raj_mostwanted]

but dude its 7 mrks q lol

[yesioo]

darn i picked the wrong one. It's a resit from January.

How much do we need to know about esters? I struggle remembering how they are formed from alcohols or carb acids. My chemistry teacher keeps going on about acyl something. Also I can't name molecules for toffee aha. The 3rd should be interesting.

[HotCoco.]

Originally Posted by raj_mostwanted

but dude its 7 mrks q lol

I've done that question before and saw the mark scheme but I've kind of forgotten LOL!

Definitely one of the answers is to add dilute silver nitrate and observe the rate of reaction.

I believe the answer also requires you to explain why chloroethane would react faster than bromoethane, which in turn would react faster than Iodoethane.

And perhaps your observations (somebody correct me if i'm wrong about all this.)

[HotCoco.]

Originally Posted by AnythingButChardonnay

Chemistry is my worst subject, which is especially distressing given that it is my most important subject, and given the extent to which I ballsed-up physics on Thursday.

I find the various types of addition extremely confusing.

Aww chemistry is the subject I'm most confident about. It's biology OCR i'm scared about. So much to remember!! But just do the end of chapter questions in that chapter about addition reactions and you'll be fine.

I wish the Biology OCR text book had end of chapter questions like the chem one. You'd think coming from the same examining board that the books would have a similar layout?

[raj_mostwanted]

Originally Posted by HotCoco.

I've done that question before and saw the mark scheme but I've kind of forgotten LOL!

Definitely one of the answers is to add dilute silver nitrate and observe the rate of reaction.

I believe the answer also requires you to explain why chloroethane would react faster than bromoethane, which in turn would react faster than Iodoethane.

And perhaps your observations (somebody correct me if i'm wrong about all this.)

looks like u on ur way for A

[AnythingButChardonnay]

Originally Posted by HotCoco.

Aww chemistry is the subject I'm most confident about. It's biology OCR i'm scared about. So much to remember!! But just do the end of chapter questions in that chapter about addition reactions and you'll be fine.

I wish the Biology OCR text book had end of chapter questions like the chem one. You'd think coming from the same examining board that the books would have a similar layout?

Is your chemistry text book a little red one? I don't like it very much at all.

My school does OCR for pretty much everything except biology. Maybe there's a good reason for that!

[steph_v]

I took Unit 1 in January and got a B. But I wish my school would let me retake, because I think I've got more chance of getting an A in Unit 1 than Unit 2. And I NEED an A or bye bye to vet school dreams.
I really don't like Chemistry. I'm so scared about this exam. I've done lots of past papers, but they didn't go too fantastically. I did the Specimen paper under test conditions at school and got a C Then again, when I did the Specimen paper for Unit 1 I got an E, and a low E at that!

[clad in armour]

http://www.whsmith.co.uk/CatalogAndS...844894345.html
anyone use this textbook

[clad in armour]

Originally Posted by steph_v

I took Unit 1 in January and got a B. But I wish my school would let me retake, because I think I've got more chance of getting an A in Unit 1 than Unit 2. And I NEED an A or bye bye to vet school dreams.
I really don't like Chemistry. I'm so scared about this exam. I've done lots of past papers, but they didn't go too fantastically. I did the Specimen paper under test conditions at school and got a C Then again, when I did the Specimen paper for Unit 1 I got an E, and a low E at that!

im already ******** it because ive done **** in all my may/june exams at the moment and wont be able to apply for med school
I just scratched an A 72/90