[化學]2題普化
看板TransBioChem作者I34001019 (fuygfujhilku)時間12年前 (2012/03/26 00:13)推噓0(0推 0噓 0→)留言0則, 0人參與討論串1/2 (看更多)
1 If 155J of heat is given off by a system and the system does 775J of work
on the surroundings,what is the initial energy change for the surroundings?
(A)-930J (B)-620J (C)+620J (D)+930J (E)none of all
答案為(A)
個人解法
這題用熱力學公式可以知道
deltaE=Q+W
=-155+(-775)=-930J
但我想說題目最後一句話不是說for the surroundings
我就以為答案是+930J
結果錯了= =""
2 A real gas usually cools slightly if it is allowed to expand adiabatically
into an evacuated container.Which of the following statements is TRUE,if
it is an ideal gas?
(A) The temperature will cool slightly, too.
(B) This is an isothermal process.
(C) deltaE = Q+W
(D) deltaE = 0
(E) deltaH = 0
答案為(B)(C)(D)(E)
我的答案為(A)(C)(D) 一口一""
個人解法
(A)我看到gas usually cool slightly 我就選(A)了
(B)我想說絕熱應該不是等溫 所以我就直接跳過這個選項了
(C)為基本公式
(D)因絕熱和真空膨脹 Q=0 W=0 故delta E =0
(E)因為我想說不是"定壓"下才會delta H = Q = 0
然後題目沒有說定壓 所以我就沒選了...
不知版上大大認為我是觀念哪裡錯誤 還是 題目有瑕疵呢?
感謝大大為我指點迷津^^"
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