15 replies to this topic

[James]

What do you think are some important facts from Higher Chemistry? Facts that people like myself could learn at the last minute and scrape a mark or two.

[Nathan]

know all the naming rules, excess calculations, hess's law, nuclear chemistry and chemical industry

however, a week is still plenty of time

[Pammy]

This is one of the summary sheets I have written for myself and thought I would share it with you


In equilibrium reactions
* low temperature favours the exothermic reaction
* high pressure favours the reaction where less gas molecules are formed

If in an equation you see H O (g) you need to be aware that the temp. must be above 100 degrees as it it normally liquid !!

Water and Ammonia are polar (although I think they shouldn't be!!)

All ionic compunds are solid at room temperature

"Like dissolves like" - why alcohol and water mix (both polar covalent) and why oil (covalent) and water(polar covalent) don't mix.

Kevlar is an aromatic polyamide and contains hydrogen bonding

Giant covalent Network- Silicon dioxide(sand/glass), diamond

All fats are esters

One mole of any gas, under the same temperature and pressure, has the same mole of any other gas.

Volumes of gases are proportional to the number of moles present.

[Michael]

All the modern polymers and the types of reaction for example, oxidation, reduction, dehydration, hydrolysis etc etc.

[AM4R]

This is one of the summary sheets I have written for myself and thought I would share it with you


In equilibrium reactions
* low temperature favours the exothermic reaction
* high pressure favours the reaction where less gas molecules are formed

If in an equation you see H O (g) you need to be aware that the temp. must be above 100 degrees as it it normally liquid !!

Water and Ammonia are polar (although I think they shouldn't be!!)

All ionic compunds are solid at room temperature

"Like dissolves like" - why alcohol and water mix (both polar covalent) and why oil (covalent) and water(polar covalent) don't mix.

Kevlar is an aromatic polyamide and contains hydrogen bonding

Giant covalent Network- Silicon dioxide(sand/glass), diamond

All fats are esters

One mole of any gas, under the same temperature and pressure, has the same mole of any other gas.

Volumes of gases are proportional to the number of moles present.

Nice one Pammy!

[Nathan]

y'know this is just gonna end up being most of the course, james

also, you should probably know your alcohols, what they can be oxidised with, what they are oxidised too, etc

[James]

I think your right Nathanm. There is so many things to remember.

Just keep posting any important facts you can think of.


Thanks folks!

[Pammy]

This is in another thread, but I thought I'd repost it for you

Reactions

Condensation: Molecules combine, releasing a small molecule (usually water) at each join. For example, when acids and alcohols form esters and when amino acids form proteins.

Hydrolysis: The opposite of condensation. A larger molecule breaks apart as water is added to it. For example, when an ester breaks down to acid and alcohol.

Oxidation: Addition of oxygen or removal of hydrogen, decreasing the ratio of oxygen to hydrogen in a compound.

Addition: Double or triple bonds open up and bond to other atoms. A double bond adds one mole of a compound e.g bromine. A triple bond adds two moles of a compound.

Hydrogenation: Addition of hydrogen.

Dehydrogenation: Removal of hydrogen.

Hydration: This is addition of water to the double bond, as an H to one atom and an OH to another. It can be used to convert an alkene to an alcohol.

Dehydration: The opposite of hydration, often catalysed by aluminium oxide. Actual products depend on where the double bond is located in the molecule.

Addition Polymerisation: This type of polymerisation results from addition of molecules across double bonds. It can only occur when the monomer has a C=C double bond.

Condensation Polymerisation: This type of polymerisation occurs when monomers have two functional groups, enabling the condensation reactions to take place at each end of the molecule.

Cracking: This involves long chain alkanes being broken down into shorter alkanes and alkenes. Heat and a catalyst (aluminium oxide) are often required.

Reforming: This is really a set of reactions, which rearrange the atoms in an organic molecule, without greatly altering the number of carbon atoms.

[AM4R]

just came into my head, what is displacement again?

alsooooooooo we will need to know all the calculations!

[Nathan]

just came into my head, what is displacement again?

alsooooooooo we will need to know all the calculations!

displacement is when a metal above in the electronegativity series removes one below it from solution and it goes into solution...a pretty poor explanation, but it's basically redox stuff

[AM4R]

got ya! Thanks

[Ali89]

One thing that I have found REALLY useful is that UNIT 2 FLOW CHART from this site! It's great - especially if you write your own notes on it like Oxidising agents etc.

For me anyway, Calculations would be the thing to look at - as Im pretty duff at them!


Edit: sorry, just realised that aint a fact like you were looking for!

but whilst im at it - PPA's are pretty good to learn up!



Also -

Atomic size decreases across a period
Increasing electronegativity across a period
General increase in 1st ionisation energy across a period


Then the opposite for going down a group

[eyecandy]

whats the gfm triangle again? i always mess up calculations

[ph!l]

Knowing all the PPA'S is very useful as they always come up and is a good source of easy marks. They have all the PPA'S in the resources section for Chemistry: http://www.hsn.uk.net/resources/HSN14310. Also knowing all the formula is obviously useful Good luck!

whats the gfm triangle again? i always mess up calculations

Mass
Moles x GFM

Moles
Volume(l) x Concentration

Eh
c x m x change in T

Q(charge) = I(current (amps))t (seconds)

[eyecandy]

[quote name='eyecandy' post='81247' date='May 23 2006, 11:38 PM']
whats the gfm triangle again? i always mess up calculations
[/quote]

Mass
Moles x GFM

Moles
Volume(l) x Concentration

Eh
c x m x change in T

Q(charge) = I(current (amps))t (seconds)
[/quote]

thaaank u

[Ally]

If you're wanting to look at PPA stuff then also visit the following thread. Bred's produced answers for all of them.
http://www.hsn.uk.net/forum/index.php?showtopic=377