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I know this is a pretty stupid question to ask, but I'm dying without the answer I know about observing the following factors: - Colour change - Heat change - New substances formed But, say if we add cold milk into hot tea. Initially brown, the milk slowly turns it into white. Now there is a...

EDIT: Oops, I only just realised that I was 4 years late. It's made using an industrial process called saponification. Basically, an ester is boiled with sodium hydroxide (NaOH). The common esters used are triesters, and they are usually triglycerides. They're basically made up of animal fats...

Try Cambridge/Fitzpatrick on a regular basis. It's good for a good background.

Well it's posted in the chemistry section, so I'm assuming it's chemistry.

Aren't you in year 10? lol

20b) Sorry, I gave a wrong answer in my previous post. Lead acid cells are recharged by applying a voltage to reverse the spontaneous chemical reaction that occurs when the cell delivers current.

That part is incorrect. You still need one more step. pH = -log [H+] = -log (n/0.07)

Chemical properties are more about the reaction of the substance. E.g. A physical property of octane would be that it's liquid at room temp, it has X degrees boiling point, transparent liquid, etc... Chemical property would be that it would ignite easily in oxygen to undergo combustion.

Just keep doing past papers for 2u. Do about 10. Make sure you mark them. There should be improvement xD

Aww, I regret so much not paying attention in earlier years. I only started loving chemistry in year 11 =( I never cared about any shit in junior years. Now I missed my chance of chemistry olympiad =(

2007 Industrial chemistry section. There was solid in the equilibrium. You just have to ignore it in the equilibrium expression.

Well I don't know why a N:P ratio would drop, but it's just simple maths. 20:1 to 2:1 would be a drop in N:P ratio, yes. So yes, if you add more neutrons, then you'll just have a higher ratio. It won't decrease.

Umm, I think it's only aqueous and gas.

Umm... I'm not sure if this will answer your question, but low N:P = high P:N. lol =O wikipedia would've been useful for that But it's when a stable element/molecule/whatever gets ionised, ie. by giving them a charge by either taking away or giving it more electrons.

lol I think you have the right idea. Your explanation was worded quite weirdly (to me), but yes. H-bonding is basically dipole/dipole, except they're called H-bonding because they form stronger dipoles with O/N/F.

Re: 回复: Re: Question 18 from 2008 exam lol that's why I asked what exam is this from... I don't like this question at all. Why would they allocate 4 marks on this question? There's not so many things to talk about =O And dude...Did you mean your school trial or something?

Sorry I don't get your post.

Which exam is this?

No units.

This is outside the syllabus, so unless you really want to know why, just remember that K is only dependent on temperature. There are actually lots of different types of equilibrium constants. There is one for concentration, one for pressure, one for temperature, pH.... LOTS The "K" we are...