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什么是ph VALUE?
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什么是ph VALUE?
P=? H=?
请问洗头水的 ph是多少？、为什么有人说是5.5？ |
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发表于 30-7-2007 10:38 PM
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pH means "power of H+" (ie. power of hydrogen ion)
pH of shampoo is 4 to 5.5. That's because our skin/hair natural pH is 5.5 |
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楼主 |
发表于 2-8-2007 07:21 AM
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原帖由 mikata 于 30-7-2007 10:38 PM 发表 
pH means "power of H+" (ie. power of hydrogen ion)
pH of shampoo is 4 to 5.5. That's because our skin/hair natural pH is 5.5
our skin /hair is acidic is 5.5 ph is right.so ...we need shampoo to neutral it.so that shampoo must in alkalin. my test book oso say shampoo is alkaline...but...why u say shampoo is 4-5.5???? acid can neutral acid???? |
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发表于 3-8-2007 10:39 PM
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It's not about neturalization. It's abt the sensitivity of ur skin to pH. If you use shampoo that suits the pH of your hair/skin, ur hair/skin will be less allergic. Since our ideal hair/skin pH is of 4-5.5, using the similar pH shampoo is more suitable.
Besides, neutralization only happens between a strong acid and alkaline substance, substances that range from weak acidic 4-7 and weak alkaline 7-9 will not neutralize each other, they simply remain their acidity and alkalinity.
[ 本帖最后由 mikata 于 3-8-2007 10:41 PM 编辑 ] |
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发表于 21-8-2007 06:27 PM
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ph value can be calculated by -log[H+]
it means tat.. the higher the H+ concentration, the lower the ph value
on the other hand, you can also says that, [H+][OH-]=10^-14
so the these two equations can be implemented in different ways to figure out the ph value |
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发表于 21-10-2007 05:00 PM
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原帖由 西界来的魔鬼 于 2-8-2007 07:21 AM 发表 
our skin /hair is acidic is 5.5 ph is right.so ...we need shampoo to neutral it.so that shampoo must in alkalin. my test book oso say shampoo is alkaline...but...why u say shampoo is 4-5.5???? ...
ya, you are right, no matter shampoo or soap should be in alkaline form, because NaOH and gliserol is the basic ingredients to produce soap/shampoo. so that shampoo/soap must be in alkaline form. |
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发表于 23-10-2007 11:35 PM
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发表于 19-8-2011 11:52 AM
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不是不可以用英文发帖吗？=.=
soulplayer 发表于 23-10-2007 11:35 PM 
版主没有管 |
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发表于 19-8-2011 12:11 PM
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什么是ph VALUE?
P=? H=?
请问洗头水的 ph是多少？、为什么有人说是5.5？
西界来的魔鬼 发表于 30-7-2007 11:03 AM
pH值
亦称氢离子浓度指数
是溶液中氢离子活度的一种标度,也就是通常意义上溶液酸碱程度的衡量标准
通常情况下,pH值是一个介于0和14之间的数
当pH<7的时候,溶液呈酸性 ACID
当pH>7的时候,溶液呈碱性 ALKALINE
当pH=7的时候,溶液中性
洗发水pH值需要test
好的洗发水pH值大多在5.9左右，呈弱酸性
因为头发丝耐酸性较强
就怕碱性的东西
所以洗发水最好选用弱酸性的和中性的
(我google来的) |
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