纯水是否导电？

sonuvdabitch

雨天之魂 于 31-8-2004 02:06 AM  说 :



再补充一点点。。纯水噢。。我强调纯水哦。。是不会有 ionic bond 的。
水跟水之间是 hydrogen bond..　H 跟　OH 之间是 covalent bond.

重点就是一定要是纯水。。。如果有。。比如说　Na+ 在里面。。那 ...

如果是kovalen的話怎麼分解MgSO4

雨天之魂

请看志强哥在楼上的回复.

" 水当然是molekul kovalen
但是当sebatian ion 溶在水里，它的氢元素和氧元素将会变成离子
因此，水就能导电。 "

MgSO4 会不会溶解在水里面牵涉到 thermochemistry 的问题..在这儿解释太复杂...
简单来说, 一个物质会溶解在水的意思就是水的 molecule 会和它 form bond.

你知道 MgSO4 是 ionic compound 吧 ? 在水里面, 它们会化成 Mg2+ 和 SO42-.
而这两种 ions 不会令 H20 分解...水的 molecule 会直接被吸引过去. (H20--Mg+--H2O), 不会有 H+ / OH-　的产生．

ion 跟 ion间会形成 ionic bond... ion 跟 molecule 呢 ? 那个叫 ionic-dipole attraction..算是一种 Van der Waals forces...(马来文叫 ikatan van der waals 吧 ?)   

回到导电问题的话，　你要加入 acid/base 才能够令水分解出更多的 H+ / OH-　来导电． 加 MgSO4　当然也行．．可是导电的是 Mg+ / SO42-.. 而不是纯水．．明白否　？

[ Last edited by 雨天之魂 on 31-8-2004 at 03:41 PM ]

雨天之魂

又， louiektc 兄在楼上发表的那些东西其实已经足够解释这个问题有余．．

哇劳呃．．．真的是太过学术性了啦．．．　先向您行个礼．．．佩服你的毅力．．

就是有一点点困扰．．会问这个问题的应该不太容易明白那些专业名词吧．？　

Asurahyde

嚴格來說﹐任何一個體制都能導電﹐只要電場大得足夠breakdown空間的dielectric properties就行。

閃電其實就是用這個原理。

森崎二郎

小李波特 于 29-6-2004 05:06 PM  说 :
导电的条件是什么？

If you try to make pure water by gradually removing electrolytes, its conductivity gradually decreases. So, if all electrolytes are removed, will its conductivity become zero? No. Why? Because an infinitesimal part of the molecules of water--only about one in 500 million--is ionized as hydrogen ions (H+) and hydroxide ions (OH-). Theoretically, at this point, the conductivity becomes 0.0548 µS/cm at 25 °C.

The conductivity of ultra pure water used in the production of VLSIs in the semiconductor industry is below 0.06 µS/cm-- that's water of very high purity indeed.Without going to such an ultrapure level, conductivity of water can be lowered to below 1 µS/cm through a process of deionization. Such water is called ion-exchanged water or deionized water. When we talk about pure water, we refer to water of this level of purity. When water comes in contact with air, carbon dioxide(CO2)  is dissolved in water, causing its conductivity to rise by about 1 µS/cm. This does affect the conductivity of pure water.

Everything is relative, so yes, it will conduct electricity--but very little compared to city water, well water, or salt water. The reason is that the way a liquid conducts electricity is through positively or negatively charged ions that are in it actually moving from one of the electrodes to the other, carrying charge (electricity) with them. Salt water has salt in it, NaCl, which readily ionizes or dissociates to ions of Na+ and Cl- which can float through the water carrying charge and thus conducting electricity.

Pure water can conduct electricity,the reason is that the way a liquid conducts electricity is through positively or negatively charged ions since water can also undergoes  ionization itself  to H+ and OH- like salt does, but it ionizes far, far, less and is therefore quite resistant to conducting electricity.

So the answer still yes, but we better saiid to what degree of conductivity or relativity.

tungtung

志强 于 25-7-2004 12:19 AM  说 :
为什么错呢?
恳请您解答.

is due to the hydrogen bond makes the 'pure water ' conducting current.
louiektc had explained all this above

森崎二郎 于 13-9-2004 11:23 PM  说 :

The conductivity of ultra pure water used in the production of VLSIs in the semiconductor industry is below 0.06 µS/cm--
  ...

表面来看,旧技术用来生产VLSI晶片的水的确需要用高质量低导电率的纯水.不过去离子水(DI)就如绝缘材料会附带高幅度的静电.当去离子水划过晶圆片的表面时,电路上的氧化硅闸门(GATE OXIDE)会受到去离子水中的静电诱导而被击穿,晶体管被破坏.接下来那个闸极也就失去起功能了,白白给浪费掉了.

在小于0.18微米的VLSI的生产流程中,一般上被蚀刻分隔后(GATE ISOLATION ETCH)的氧化闸的厚度是在35到90埃(ANGSTROM, 一埃相等于一粒氢原子的大小),宽大约700到2000埃不等..如果在闸门分隔后的清洗步骤用了较高导电率反滲透水掺杂二氧化碳(CO2 DILUTED REVERSE OSMOSIS K=0.95 到 1.0µS/cm),氧化硅闸们会一较温和的方式泻掉静电,或不容易被充电而长期避开处在高电荷的状态.在后来的生产流程里反而是高导电率的纯水比较适合.

高质量低导电率的纯水对金属表面有很强的攻击性.比如说,把铝或铜突然浸入去离子水里边,铝的表面马上产生微凹洞(MICRO-PITTINGS),而去离子水的电阻值即刻下堕,因此去离子非常不利于金属接线的生产程序.

简单来说,当从以上一两个冰角来看,理论上的完整性,需待实践后才能带出个造的整合性.

tungtung

不名百你在说身什么 ?????

electronic de dong dong!!!!

(警告no.1)請以中文發言﹐謝謝。

[ Last edited by Asurahyde on 27-10-2004 at 01:54 PM ]