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標題: Re: 嗚
時間: Sat Oct 18 23:04:30 2003
好哇.................(開始後悔高中化學都不碰了，嗚嗚，連個基礎都沒有)
先一兩題好了
*. A buffer solution contains 0.1M CH3-COOH and 0.1M sodium acetate (that
is, it is a 0.2M acetate buffer). Calculate the pH after addition of 4ml of
0.025N HCl to 10ml of the buffer. The pKa for acetic acid is 4.74 .
Answer: pH=4.65
我自己是這樣想的：
CH3-COOH + NaCl <=======> CH3-COO-Na + HCl
pH = pKa + log CH3-COO-Na
CH3-COOH
==> pH = 4.74 +log CH3-COO-Na
CH3-COOH
然後就卡了，算出來跟老師給的答案不一樣...TT
=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++=
*. Describe the preparation of 1 liter(L) of a 0.1M ammonium chloride buffer,
pH 9.0, starting with solid ammonium chloride (pKa = 9.26 ) and 1M NaOH.
這題我完全不知道怎麼下手.......
它的反應式是 NH4-OH + HCl <===> NH4-Cl + H2-O 嗎？
《最後編修日期：10/18/2003 23:05:06 Sat》
--
┌┌┌┌ Origin: 小魚的紫色花園 <fpg.twbbs.org> 140.112.200.214 ───┐┐┐┐
好哇.................(開始後悔高中化學都不碰了，嗚嗚，連個基礎都沒有)
先一兩題好了
*. A buffer solution contains 0.1M CH3-COOH and 0.1M sodium acetate (that
is, it is a 0.2M acetate buffer). Calculate the pH after addition of 4ml of
0.025N HCl to 10ml of the buffer. The pKa for acetic acid is 4.74 .
Answer: pH=4.65
我自己是這樣想的：
CH3-COOH + NaCl <=======> CH3-COO-Na + HCl
pH = pKa + log CH3-COO-Na
CH3-COOH
==> pH = 4.74 +log CH3-COO-Na
CH3-COOH
然後就卡了，算出來跟老師給的答案不一樣...TT
=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++=
*. Describe the preparation of 1 liter(L) of a 0.1M ammonium chloride buffer,
pH 9.0, starting with solid ammonium chloride (pKa = 9.26 ) and 1M NaOH.
這題我完全不知道怎麼下手.......
它的反應式是 NH4-OH + HCl <===> NH4-Cl + H2-O 嗎？
《最後編修日期：10/18/2003 23:05:06 Sat》
--
┌┌┌┌ Origin: 小魚的紫色花園 <fpg.twbbs.org> 140.112.200.214 ───┐┐┐┐