Horza2002

Diamond probably since it is the hardest known material.

There is a molecules called adamantite....its is a tribridged cyclohexane ring

It depends...somedays it doesnt freeze at all, other day it freezes the first time i put it on and play for about 15mins then not again after....

My PS3 seems to freeze from time to time and then I have to turn it off and and on again before it works. Does anyone know why this happens??

We're also now waiting to see which policies from each party (Torries and Lib Dem) will be used for this new government. Again, it all happened very suddenly yesterday. In the morning, Labour where still negotiating with the Lib Dems to get a deal which collapsed around 5pm.

It seems very different over hear then. In most cases, Prime Ministers resign when they leave office. Most likely because they don't like the idea of having to face the new PM from the opposition benches

u might be able to sublime one of them

The rate determining step of a SN1 only has one molecule (this is usually a group falling off the molecule). For an SN2, the rate determining step involves two molecules (the electrophile and nucleophile normally)

Thats not stricly true. The equation for change in Gibbs energy is

G = H -TS

If the reaction has a positive change in entropy (S) then an increase temperature will indeed favour a reaction. However, if the change in entropy is negative then a decrease in temperature will make a more favourable gibbs energy.

This arises because the entropy of a system depends greatly on the temperature of a system

Well sevral affects can affect where the peaks occur. A major one will be concentration of ur sample. I have observed signals that move up to 1ppm simply by changing the concentration. Temperature is another major influence on the position of the peaks.

The simple ones like using acids and bases can be epeccted if you look at the mechanism. Others have been designed to work (e.g. Wilkinsons catalyst)

I extremely doubt that the water lysed under those conditions. What probably happened was that the water boiled instanly which expanded and blew the flame outwards like a gust of wind moves a flame.

The orange colour is most likely a result of the presence of sodium ion in the water...sodium has a characterisc orange glow to it

When the mixture is hot, benzoic acid will dissolve in it. Once it begins to cool down though, it'l get to a point where it is insoluble in the mixture and so will crystalise out

Pioneer, the difference between the reactant and product is the change in Gibbs free energy I described above.

The height of the activation barrier has no effect on the amount of energy that is released. The height of the barrier only controls the rate of reaction (i.e. the kinetics) not the thermodynamics.

An run away explosion may occur if there is a large energy difference and a small barrier height, but you need both conditions for that to occur.

If you only consider enthalpy (thats changes in bond strength) then yes, endothermic reactions are erasy to reverse. HOwever, for a reaction to occur, the change in Gibbs free energy has to be negative. This depends on the change in enthalpy and entropy.

[math]\Delta[/math]G=[math]\Delta[/math]H-T[math]\Delta[/math]S

If the entalpy is positive (i.e. endothermic) then the change in enthalpy (S) has to be very positive to overcome this.

So if a reaction is endothermic, there has to be a large increase in the disorder of the system to make it work.

Well for the hydrogenation, try looking up Wilkinsons catalyst. That is a ruthenium based homogenous catalysts for reducing alkenes to alkanes.

The ester one is an example

And certain bacteria in the proteasome use a catalytic water molecule in the degredation of proteins

No. At 0K, the atoms are in their ground states of translational, rotational, vibrational and electronic states. Even at this level, the electrons will still have their lowest energy possible.

The pi-stacking especially will help stabilise protein structures that contain several aromatic rings. The major contributing factor that holds DNA together is by pi-stacking of the aromatic bases (not the hydrogen bonds between strands). So any structure that contains an indole may help hold an enzyme in the correct shape.

There is a generalised bonding theory....it comes from orbital overlap with the fomration of bonding/antibonding orbtials. VSEPR breaks down because the d-orbitals have two different symmetry lables (t2 and e) and so it doesn't work anymore.

You need to consider the stability of the products. When you burn petrol, the products (carbon dioxide and water) are far more stable than the starting petrol. This energy that is released on forming the strong bonds is what is given out as heat.

There are some reactions that actually get colder as they react because the products are less stable than the starting material (have a look for endothermic reactions)

Every reaction will require a different catalyst depending on whats going on.

Hydrogenation with hydrogen requires a metal catalyst (normally palladium)

Esterification usually requires an acid

Some biological reactions use catalytic water

Yeas sharp on an atomic scale has a very large effect in imaging. The resolution obtained from scanning tunnelling microscopy is determined on how sharp u can get the tip of microscope. The best resolution possible is obtained with a point of a single atom.

It has a hydrogen (attatched to the nitrogen) capbable of forming hydrogen bonds. It also has a large pi-electron system that is capabable of undergoing pi-stacking.

There is a magnesium atom in the centre of an aromatic heterocycle. When sunlight shines on it, an electron is "ejected" from the magnesium where it is capture by an electron acceptor. This electron is then passed along a chain of reactions that eventually lead to the biosynthesis of whatever the plant needs

http://news.bbc.co.uk/1/hi/world/europe/8577740.stm

I, personally, think that this was a very half-hearted attempt at an apology really. For starters, the Pope didn't even give it! How do people feel about this affecting the Church's reputation?

One major change would be a reduced muscle mass....same as astronauts experience. A smaller and weaker heart aswell probably

No problem. If you want me to explain it in more detail just let me know!!