1種液體wet唔wet glass取決於什麼?

2006-11-24 6:11 am
1種液體wet唔wet glass取決於什麼?
(i mean係1支liquid-in-glass thermometer入面)
同表面張力, intermolecular (van der waal's) force有冇關係?
mercury同alcohol, wet唔wet glass架?

thz!!
更新1:

可唔可以再講1講點解mercury因唔wet glass所以適合做liquid-in-glass thermometer... alcohol wet glass但係又一樣可以做liquid-in-glass thermometer呢? 唔該晒^^

回答 (2)

2006-11-26 5:15 am
✔ 最佳答案
Carman~.....
比個最佳回答我啦!!!我係lautszki呀....

你仲記唔記得我地bio學的cohesive force 同 adhesive force呀
我諗應該差唔多架
我試下幫佢番譯啦:

佢話:liquid wet 唔 wet glass呢,第一就係決定於liquid同glass的本性,第二就係intermolecular force of liquid。咁glass主要係SiO2組成,佢個surface 有好多oxide的electron pairs (lone pairs),所以就好容易同水form到H-bonding(即是有Hydrogen的bond)或者其他好似alcohol E D 有(-OH)的野 form到bond.
由於intermolecular force of alcohol 係弱過水同埋佢係屬於(-OH) group啦,所以佢比water 易D wet glass。
至於Mercury呢,佢同SiO2冇attraction,所以冇咁易wet glass。仲有一個因素係因為Hg的intermolecular force 好強,所以亦會減少左glass同Hg的力。

以下屬個人意見:

其實我認為人地都唔係好想用alcohol黎做thermometer 架o查,不過冇得揀先用o查麻。
難得佢冇毒之餘又會正比例澎漲,咁佢優點多過缺點咪是但囉.....

bio 話 cohesion係liquid裡面的吸力,adhesion係外面物質對liquid的吸力,咁我諗你所講的黏力應該係講緊自己吸自己啦可?如果係ge就係cohesion....
但係如果你想講譬如我地放隻手指係水面會吸到D水上黎呢,咁就係adhesion...
好笑呀,你試下啦,放隻手指掂住水面真係會有黏力架!!

2006-11-25 21:16:45 補充:
最後o個句漏左個"唔"字→唔好笑呀,你試下啦,放隻手指掂住水面真係會有黏力架!!

2006-11-25 21:53:54 補充:
welcome....
參考: e-class!!!
2006-11-24 7:05 am
Whether a liquid has a good wetting power on the glass, it depends on firstly the affinity between the liquid and glass and secondly the intramolecular force of liquid. The chemical composition of glass is mainly silicon oxide. On the surface of teh glass, it bears a lot of electron pair on the oxide. This can form good H-bonding with the water or anything which has the -OH group such as alcohol. Since the intramolecular power of alcohol is weaker than water and it bears also teh -OH group. It can have better wetting power than water. With Mercury, there is no additional interaction with the silicon oxide. So, the wetting power will not be as great as water. In addition, due to the strong intramolecular force within the mercury. It further reduce the wetting power of mercury towards glass.


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