Presentation on Structure and it's effect on molecule behaviour: Any idea's ?

Hi there,

This is my first post, I am currently undertaking a chemistry enhancement course so I can go onto start a PGCE in chemistry in september.

We have to do a 45 min - 1 hour presentation on a subject of our choice.

I have chosen to do something to do with structure and how this effects the behavior of elements/molecules.

Obviously this is a vast subject and I don't want to go too in depth on one particular subsection e.g. bonding, hydrogen bonding, intermolecular forces, lone pairs etc (we have already covered this somewhat in our syllabus).

I was thinking of talking about relevant points that effect the shape/geometry of a molecule (e.g. verspr module) very briefly then going on to difference in behaviors of certain compounds to highlight differences. (e.g. H2O, C2H4, Isomers branched, cyclic and straight chains, polymers) but not quite sure how i could best illustrate the importance of structure and shape on behavior...

Can anyone think of any good examples/alternative ideas i could pursue?

p.s. I am very aware that i don't want to get bogged down too much in one thing and think it would be great to touch the surface of many different examples.

thanks for any help!

Reply 1

PJ Chemnerd

One example you could use is how the bond angle in water changes when it becomes a ligand from 104.5 degrees to ~107 degrees

Reply 2

Mr Fm

Great, thanks for the advice.

I don't know a great deal about Ligands. So the angle between the the two Hydrogen's open up is what I think you mean. I suppose this is something to do with one of the lone pairs being used and thus the repulsion effect about the H's is less?

Keep them coming!

Reply 3

Mr Fm

Any other ideas guys?

Reply 4

chemicalguy

Graphites lubication and 2D electrical properties (orientation of pi-system)

Poly alkynes electrical conductivities (conjugated pi-system gives linear delocalisation)

The effect of ligand, oxidaion state and coordination number on colour of transition metal ions (altering deltaE of ground state to excited state) - just need a few examples of colour, you can ask here or see any A2

Stabilisation of usually unstable oxidation states by ligands etc Co3+ by ammonia etc...

just a few to make you think...

Reply 5

chemicalguy

OMG I can't stop 'em coming now...!

Differences of melting and boiling point for cis-trans isomers

Effects of enantiomers (non-superimposable mirror images due t chirality) on plane polarised light...

This is fun ... for a chemist 8(

Reply 6

chemicalguy

get them out of my head...aaargh!!

Effect of R-group branching on Sn1 and Sn2 mechanistic behaviour of halogenolkanes (steric hindrance = Sn1, non-hindered = Sn2... that one came to me in the shower ... I never realised I was quite so sad!

Reply 7

chemicalguy

Now am on fire:
The biological pointless ness of D-amino acids
Oil of wintergreen and its other stereoisome (that I cant remember)
Keto-enol tautomersm
conjugation causing combined effects causing alteration of properties like benzene undergoing substuitution not addition
altering azo dye colour through modification of nductive group on the arene

I think I'll stop now I'm getting too geeky...

Reply 8

Mr Fm

That chemical guy! You have given me a lot to think about!

A lot of those idea's I have never come across but I'll look into them and see if I can fit any into my presentation.

I am going to include a basic interactive task where by make molecules working out their shape and geometry.

Can anyone thing of any other interactive tasks I can perform? (Basic)

Reply 9

chemicalguy

Just a thought but watch some back episodes of Brainiac: science abuse on sky - they are full of simple, visual, examples of real science (but I dont recommend you blow up a caravan with francium...

Good visual models to show differences in stereoisomer's properties could be to use hand and glove analogies for L-amino acids being recognised by one receptor (the left glove) but not the right (D-amino acid).

Making models of cis and unsaturated and saturated fats, shows how packing can take place and consequent effects on mpt and so why one is oil and one is fat.