原帖由 Royal 於 6/11/2007 05:40 PM 發表
thx...
早幾天有同學問了ChemFung了, 跟你的答案一樣
但甚麼是priority difference呢??
---
班中不少同學也有《Chemical Calculations and Quantitative Analysis》，
係唔係真係咁有用-3-"
名命時每個functional groups都有一個先後次序
CE的話以carboxylic acid > hydroxyl > c=c > halogens or amines 就足夠了...雖然不算太準
看不到符號的話......囧
那都是"大於" c和c中間是double bond
有帖說CHEM我不太想開帖問東東~_~
有沒有人可解polar solvent & non-polar solvent 多一點?
Simple Molecular Structure 的東東在liquid state 便是non-polar solvent?
(是指molten的時候)
Polarity 不一定要apply於solubilty方面的, 有時候是用於boiling point, viscosity中....所以我不limit去講common solvent了
Polarity 可理解為unequally sharing of electrons between atoms of a molecule
不清楚你對polarity有多深認識，只用electronegativity 和少少geometry來看吧(需要有些Lewis structure和VSEPR的concept....我盡量選些較簡單的examples吧
圖:
pink- electrons
blue arrows- direction of electron density pull
red- covalent bond
For H2O, Oxygen is a (much) more electronegative atom than hydrogen, electrons in the molecule would tend to stay closer to the oxygen atom rather than the two hydrogen atoms. Moreover, due to the bent structure of water molecules by the lone pairs of electrons, effect of polarity is shown above. [CE不用去理會molecular geometry, 偶已經儘量簡化了,不明也沒關係，最主要先知道electronegativity difference (CE一定有教) 不同時，就很有可能是polar (不一定是)]
For HCl, as chlorine atoms are more electronegative than hydrogen atoms, electrons of the molecule would tend to stay more on the chlorine side, resulting a more negative charge on the chlorine side. This cause a polarity of the molecule.
For hydrogen gas, since there is no electronegativity difference between the two atoms, it is a non-polar molecule.
另一個example 是 CCl4(點我看右面的3D圖), 有electronegative difference,但亦是non-polar....沒VSEPR concept的話說都只能盲目地接受
啊...
對不起對不起...
我經常問問題也會用反問的...
是我中文問題而已....是我的錯 
這樣去想名暫時都沒大問題的
[ 本帖最後由 fish 於 6/11/2007 08:56 PM 編輯 ] |
發表於 6/11/2007 08:52 PM 
發表於 9/12/2007 09:40 PM