STPM化学专区

醉痴雪

回复  yhuai


上网看了看。。
看到这个。。
http://pdfdatabase.com/organic-chemistry-stpm.html
...
meiling 发表于 10-4-2010 05:53 PM

感谢你！

Lov瑜瑜4ever

Magnesium oxide and aluminium oxide...
why magnesium oxide shows the highest ionic character compared to aluminium oxide de?

silent91

Magnesium oxide and aluminium oxide...
why magnesium oxide shows the highest ionic character compar ...
Lov瑜瑜4ever 发表于 13-4-2010 05:08 PM

mg has higher difference in electronegativity with O than aluminium...

有错请纠正～

醉痴雪

Ethanol dissolves in water compared to phenol.Explain this statement.

Razor_1130

有谁可以解释如何balance the ionic equations，chapter １３的。

很乱，先谢谢各位哦！

白羊座aries

有谁可以解释如何balance the ionic equations，chapter １３的。

很乱，先谢谢各位哦！
Razor_1130 发表于 29-4-2010 03:08 PM

能不能放一个example来看下?

语曦

mg has higher difference in electronegativity with O than aluminium...

有错请纠正～
silent91 发表于 13-4-2010 06:52 PM

in additon,aluminium oxide is ampherioic oxide.the bonds between aluminium and oxygen is covalent bonds.actually.correctly me if mistake.

Razor_1130

课本的例子都会，你有其他的例子可以给我看吗？谢谢

silent91

Ethanol dissolves in water compared to phenol.Explain this statement.
醉痴雪 发表于 28-4-2010 07:48 PM

phenol forms a stearic hidrance which "block" the water molecules forms intermolecular hydrogen bond with the OH group.
P:S: phenol is still soluble jz not as soluble as ethanol.

有错请纠正

语曦

phenol forms a stearic hidrance which "block" the water molecules forms intermolecular hydrogen  ...
silent91 发表于 2-5-2010 04:49 PM

    in addition,the electron of oxygen will delocalise the benzene ring.thus,the electronegativity will decrease.so, the hydrogen bonds are more difficult to form than ethanol.

silent91

in addition,the electron of oxygen will delocalise the benzene ring.thus,the electronegati ...
语曦 发表于 4-5-2010 06:12 PM

    完全没有想到～在下佩服～

语曦

完全没有想到～在下佩服～
silent91 发表于 4-5-2010 10:57 PM

    乱来的。。。

四月一日的小皮

in addition,the electron of oxygen will delocalise the benzene ring.thus,the electronegati ...
语曦 发表于 4-5-2010 06:12 PM

不错，你一定有机会拿A的。

lokejiunnwoei92

谁可以解释给我听mass fragment要怎样分出来ions??如题：C3H6CI2

醉痴雪

stearic hidrance
delocalise
谁能解释这两个term?

silent91

stearic hidrance
delocalise
谁能解释这两个term?
醉痴雪 发表于 19-5-2010 11:55 PM

stearic hidrance 类似障碍物的意思。

delocalised 好像是固定的意思。

（有错请纠正）

956433

stearic hidrance 类似障碍物的意思。

delocalised 好像是固定的意思。

（有错请纠正）
silent91 发表于 20-5-2010 04:19 PM

delocalised 好像是不固定的意思。
localised 才是固定的意思。
（有错请纠正）

meiling

stearic hindrance
delocalise
谁能解释这两个term?
醉痴雪 发表于 19-5-2010 11:55 PM

stearic hidrance:有点类似障碍物，如楼上所说的
如果你要深入解释+应用你可以看以下我写的
你可以看organic halogen compound的那一课，有Sn1 Sn2的
steric hindrance是用来解释为什么tertiary halogen react with OH ion要用Sn2
for tertiary halogen,it is bonded to 3 alkyl group. so this 3 alkyl group can be said as big things and the OH ion can't get into d tertiary halogen by Sn1(by Sn1 the hydrogen ion 是用挤进去的). so this condition is mean as steric hindrance.

delocalise：
我们用这个句子来解释
in addition,the electron of oxygen will delocalise the benzene ring.
大概是这样讲oxygen in phenol has 2 lone pairs. one of the lone pair will move into d ring of benzene. this is call as delocalisation.

meiling

谁可以解释给我听mass fragment要怎样分出来ions??如题：C3H6CI2
lokejiunnwoei92 发表于 19-5-2010 10:01 PM

其实很简单，但是要在这里画出来有点难，希望你不会看到mcc

题目给你C3H6CI2

你要先画出来，比如我认为是这样的排列(我没有画H出来)

Cl-C-C-C-Cl

所以当你用mass fragment弄出来的时候你会看到
CH3Cl  CHCl
意思就是切割，但是也有可能是这样

C-CCl-C-Cl

所以切割出来又不一样了
这样你能明白么？
最主要就是你的isomerism要学好，然后就简单了，我记得是切割C-C的bond，所以不太确定有没有切割C-Cl bond

lokejiunnwoei92

回复 599# meiling


哦。。明白明白。。谢谢