Some more Qs on chem

Q2
we won't pick out the C=O and say it is a carbonyl group because it is included in the C(=O)O this entire thing, which is considered as the ester group
i.e. we won't pick out part of a functional group and say the picked part is another functional group

2012-06-05 18:01:14 補充：
Just like carboxylic acid, -COOH,
you won't say it contains a hydroxyl group(-OH) and a carboxyl group, won't you?

Hope you understand what I'm saying.

2012-06-09 21:59:43 補充：
Not quite, because even in some books, TO MAKE STUDENTS UNDERSTAND,
they might say that "ester group = carbonyl group linked to an O-atom"
and similarily "carboxylic acid group = carbonyl group + hydroxyl group" etc.
which are all quite misleading

2012-06-15 12:43:51 補充：
去死la Ming, 系度呃分！

2012-06-15 13:23:53 補充：

圖片參考：http://imgcld.yimg.com/8/n/HA00656648/o/701206040035113873410260.jpg

Hope my answer is much useful than the valueless ones. =]

2012-06-16 13:53:16 補充：
I think it is because its concern with the protective oxdie layer of Al.
But I would say reactions do occur.

For Al,
2Al + 6HCl --> 2AlCl3 + 3H2
For Al2O3,
Al2O3 + 6HCl --> 2AlCl3 +3H2O

But similar to Pb,
the product(AlCl3) formed a fine protective layer that hinder further reactions.

2012-06-16 13:56:19 補充：
I think the reason of saying there is no reaction is that the reactions only occur for short time and is not that observable.
And more importantly, it don't want to make things complicated.

1. If conc. HCl is used, product may dissolve better due to formation of complex ion [PbCl4]^(2-)

3. You have to calculate the Ksp and the exact conc. of the Ca & sulfate ions.
I've roughly estimated, shown that the product actually exceeds Ksp, meaning ppt. theoretically would form.

2012-06-16 18:15:38 補充：
Just by saying "vol. of seawater is large" is not enough.
One reasonable explanation is that, salinity and composition of seawater is NOT same / even among regions. Some are more saline, some are less.

2012-06-16 18:19:21 補充：
BTW, please locate for me the option of "贊助點數"; I could never see it.

I am very sorry. It seems your questions are very complicated. You should ask your teacher instead.

Thank you very much~ I seem that wiki has mislead me-.- When i search carbonyl in wiki i saw esters and carboxylic acids...

2012-06-10 23:04:31 補充：
this misleading concept will kill you in the exam-.- i get 1 MC wrong due to this concept

2012-06-16 22:13:59 補充：
問題-Some more Qs on chem 上面果行最左果個