作者baskball399 (Dairy)
看板TransBioChem
标题[化学] 两题化学问题！
时间Tue Jun 14 10:53:41 2011
1. For potassium, the enthalpy of sublimation is 89kJ/mol, and the first
ionization energy is 419 kJ/mol. The bond dissociation energy of Br2(g)
is 193kJ/,ol, and the electron affinity of bromine is -325 kJ/mol. The
enthalpy of vaporization of Br2(l) is 31kJ/mol. The lattice energy of
KBr is = 682kJ/mol. Calculate the overall enthapy change for the reaction:
K(s) + 1/2Br2(l) → KBr(s)
(A) +256 (B) -256 (C) -332 (D) -387 (E) -780
注：Br2(l) → Br2(L) , 括弧内的是英文字母 L 不是数字 1 .
2. A chemist dissolves 1.00 mol of a monoprotice weak acid in 100.0 mL water
and tutrates the resulting solution with 0.025 M KOH. After 20.0 mL KOH
has been added, the pH is 5.0. What is the ka value for the acid ?
(A) 1.0x10 -4 (B) 1.0x10 -5 (C) 1.0x10 -6 (D) 1.0x10 -7
注：选项中的1.0x10 -4 ，是负4。
烦请各位大大帮忙解答一下，感谢:)
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1F：→ biup2:titrate? 06/14 14:31
2F：→ biup2:[H+]= Na-Nb / Va+b Na,Nb皆需乘以倍数 06/14 14:34
3F：→ biup2:boom! i gave up 06/14 14:46
4F：→ baskball399:抱歉，我明天再确认一次有没有打错！课本在图书馆@@.. 06/14 18:44
5F：→ baskball399:没有打错，除了/mol那边之外@@" 麻烦大大解答了:) 06/15 12:16
6F：→ baskball399:对不起，是titrate，後面才发现 .... 06/18 18:16