＊＃！＆＊stupid vote... r u male or female?

sorlo

下面引用由matfz在 2003/07/27 09:31pm 發表的內容：
pH5.5 is skin ph. 中性 is pH7

maybe 佢睇得d洗頭水廣告太多

下面引用由matfz在 2003/07/27 09:31pm 發表的內容：
pH5.5 is skin ph. 中性 is pH7

hahaha...遇著個讀 chem o既人o係到。
我幫佢再解釋下喇。中性 = pH 7 or [H+] = 10^7
pH 5.5 is kinda acidic.
understand?

下面引用由NgHeiGumJa在 2003/07/28 11:02pm 發表的內容：
hahaha...遇著個讀 chem o既人o係到。
我幫佢再解釋下喇。中性 = pH 7 or  = 10^7
pH 5.5 is kinda acidic.
understand?

H+ + OH- = H2O
or
H+ + H2O = H3O+
pH = - log pKa
:em17:

H in the pH ...is that refer the Hydrogen??
2H +O=H2O
I ho chi remember that H is acidic...cos acid always has H
gam what is the Ph of water??
Neutural of Acidic???
i dun remember my Chemistry la!!!!!
=C

下面引用由debbiejai在 2003/07/30 00:06am 發表的內容：
H in the pH ...is that refer the Hydrogen??
2H +O=H2O
I ho chi remember that H is acidic...cos acid always has H
gam what is the Ph of water??
...

我都唔記得, 我讀緊o個頁條 equation 係:
NADH + H+ + 1/2O2 --> NAD+ +H2O
係 mitochondria 到....
skip 得太多堂, 讀得好慘

下面引用由debbiejai在 2003/07/30 00:06am 發表的內容：
H in the pH ...is that refer the Hydrogen??
2H +O=H2O
I ho chi remember that H is acidic...cos acid always has H
gam what is the Ph of water??
...

pH is just a range of concentration of acid or base in a solution. the H in pH doesn't mean hydrogen.
hydrogen is neutral. but H+ is acidic. H+ is just a free proton without an electron. the pH measures the concentration of H+ in a solution. in pure water, the pH should be 7. this mean the concentration of H+ in water is 10^(-7), neutral.

下面引用由NgHeiGumJa在 2003/07/30 00:33am 發表的內容：
pH is just a range of concentration of acid or base in a solution. the H in pH doesn't mean hydrogen.
hydrogen is neutral. but H+ is acidic. H+ is just a free proton without an electron. the pH me ...

wah.....ho pro and ho king ar.......

我鐘意睇"shampoo"廣告?
hahahahahahahahahaha...yeah~shampoooooooooooo~~~~~

下面引用由NgHeiGumJa在 2003/07/30 00:33am 發表的內容：
pH is just a range of concentration of acid or base in a solution. the H in pH doesn't mean hydrogen.
hydrogen is neutral. but H+ is acidic. H+ is just a free proton without an electron. the pH me ...

water PH is not always 7. MOST water is expose to air, right? like the water we drink, u don't vaccum the surrounding atmosphere, right? This will causes CO2 in the air to undergo hydrolyes and become HCO3-, the "carbonic" acid. which is acidic and found in common drinking water. The amount is slight. but that mean ph is less than 7.  :em17:  
water also undergo this reaction
H2O+H2O = H3O+ + OH-
forget why, but H3O+ should be dominate one, which also turn water acidic
i am bio major. don't trick me.  :em01:

haha..  I didn't try to trick you. but pay attention here, I said "pure" water, textbook example of pure means not contaminated. but anyways la, I am not chem major anymore, and forgot a lot la.
And you are right with your carbonic acid thing, 勁！I learned that in school too. If I have any chem question later, I'll ask you for sure la.