作者ttisc (Go to bell)
看板TransBioChem
标题Re: [化学] 台联大99两题化学
时间Wed Jun 29 00:41:47 2011
※ 引述《dumdum (好的事情)》之铭言：
: 题目如下
: 15.Give the equation A(eq)+2B(eq)←3C(eq)+2D(eq).45.0 mL of 0.050M A is
: →
: mixed with 25.0 mL 0.1M B.At equilibrium the concentration of C is 0.0410M.
: Calculate K.
: (A)7.3 (B)0.34 (C)0.040 (D)0.14 (E)none of these
用浓度(M)算
A(初):0.05*45/70=0.032
B(初):0.10*25/70=0.035
A(aq)+2B(aq)←3C(aq)+2D(aq)
初 0.032 0.035
变 -x -2x +3x +2x
------------------------------------
平 0.041
3x=0.041 x=0.0136
K=(0.041^3)(0.027^2)/(0.019)(0.008^2)=0.041
: 17.At 0‘C,the ion-product constant of water,Kw is 1.2*10^-15.What is the pH
: of pure water at 0‘C?
: (A)7.00 (B)6.88 (C)7.56 (D)7.46 (E)none of these
: Ans: 15.C ; 17.D
直接对KW开根号 取-Log kw^0.5
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1F：推 dumdum:了解了~~~~感谢你 06/29 05:35