化学高手进来下～

sunsilk_cv · 发表于 12-12-2010 04:50 PM

What is the pH of a solution that is 0.30M in HCOOH and 0.52M in HCOOK?

答案是写4.01,但是我不懂怎样做到3.53

chemistry很不dim啊～

救命下～HCOOH的Ka value是不是1.7x10^-4?

sunsilk_cv · 发表于 12-12-2010 05:04 PM

可怜0回复

sookchin · 发表于 12-12-2010 05:23 PM

HCOOH is weak acid,HCOOK is salt of HCOO-
the solution is buffer..
if want to find pH,jz substitute formula
pH= -log Ka-log(conc of acid/conc of salt)
      = -log 1.74^-4  - log ( 0.3/0.52)
      =4.008
      = 4.1

sunsilk_cv · 发表于 12-12-2010 08:05 PM

回复 3# sookchin

娃哈哈！谢谢你～知道我哪里错了～粗心啊！con. base 和con.acid倒转了

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化学高手进来下～

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