作者I34001019 (fuygfujhilku)
看板TransBioChem
标题[化学]2题普化
时间Mon Mar 26 00:13:06 2012
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
答案为(A)
个人解法
这题用热力学公式可以知道
deltaE=Q+W
=-155+(-775)=-930J
但我想说题目最後一句话不是说for the surroundings
我就以为答案是+930J
结果错了= =""
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
答案为(B)(C)(D)(E)
我的答案为(A)(C)(D) 一口一""
个人解法
(A)我看到gas usually cool slightly 我就选(A)了
(B)我想说绝热应该不是等温 所以我就直接跳过这个选项了
(C)为基本公式
(D)因绝热和真空膨胀 Q=0 W=0 故delta E =0
(E)因为我想说不是"定压"下才会delta H = Q = 0
然後题目没有说定压 所以我就没选了...
不知版上大大认为我是观念哪里错误 还是 题目有瑕疵呢?
感谢大大为我指点迷津^^"
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