作者FrogXD (FrogXD)
看板Chemistry
標題[問題] 大一普化問題，請幫我看看解答對不對。
時間Sat Apr 2 09:23:23 2011
1. This problem deals with a 0.50 M solution of the base ethylamine, CH3CH2NH2.
The pKa of its conjugate acid, CH3CH2NH3+, is 10.68.
(a) Determine the value of the equilibrium constant for the reaction.
CH3CH2NH2(aq)+H3O^+(aq) ---> CH3CH2NH3^+(aq) + H2O(l)
(b) Calculate the pH of the solution.
這題我A不會，B的話我是寫：
CH3CH2NH2 + H2O ---> CH3CH2NH3^+ + OH^-
初始 0.5
過程 -X +X +X
結果 0.5-X X X
Ka = [CH3CH2NH3^+] * [OH^-] / [CH3CH2NH2] = X^2 / 0.5
Ka值由 pka = -log Ka 換算回來 , 10.68 = -logKa , 得Ka = 2.09*10^-11
由此推出 , X^2 / 0.5 = 2.09*10^-11 , X = 1.02*10^-5
pOH = -log(1.02*10^-5) = 5
pH = 14-5 = 9
2.Assuming the gases are ideal, calculate the amount of work done, in joules,
for the conversion of 1.00 mole of Ni to Ni(CO)4 at 75°C in the reaction
below. The value of R is 8.314 J/mol‧K.
Ni(s) + 4CO(g) → Ni(CO)4(g)
3. How much heat is given off in the formation of 35.0 grams of Fe2O3(s) at
25°C and 1.00 atm pressure by the following?
4Fe(s) + 3O2 (g) → 2 Fe2O3 (s)
ΔH°f = -824.2 (kJ/mol)
後面的2.3兩題我都不會，也不知道該用到哪些公式，還有要翻高中課本的哪個單元？
想要徵個詳解，能幫我把公式完整寫出來。(我不是在做作業，我剩20天大考。)
當然，我會有酬勞啦，看要多少P幣來信附上，算是答謝！
合理範圍內我都會給，不會廢話。
有寄信的請推文，以證明我有確實給出P幣喔！(發給第一個)
有勞各位了。=]
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1F：→ FrogXD:我回來的時間會晚，但是最慢發出不會慢過24hr. 04/02 09:30
2F：→ abscented:第一題不就是Kw/Ka=Kb 04/02 13:01
3F：→ abscented:二三題去翻一下普化課本都找得到 04/02 13:04