作者Highhuman (Ryan)
看板TransBioChem
标题[问题] 一些问题
时间Fri Jul 6 15:14:24 2012
以下这几题，是我目前仍然不太会算的题目:
1.A gas sample containing of CO2 and N2 in 1:2 molar ratio has a volume of
。
350ml at 40 C with a CO2 partial pressure of 560 torr. What is the
volume of the mixed gases under STP condition ?
。
2.The decomposition of dimethyl ether , (CH3)2O , at510 C is a first-order
process wuth a rate constant of 6.8*10^-4 s^-1.
(CH3)2O (g) -->CH4 (g) + H2 (g) + CO(g)
If the initial pressure of (CH3)2O is 135 torr , how long will it take
when the pressure of (CH3)2O drops to 51 torr ?
(A)17.9 s (B)1020 s (C)1430 s (D)1.23*10^5 s
3.Consider the equilibrium :N2O4 (g) <---> 2NO2 (g)
del H = 58.0 KJ , which of the following will shift the equilibrium to the
right ?
(A) A catalyst is added to the system.
(B) N2 is added at constant volume. (我是这个选项不会 XDD")
(C) The volume is decreased.
(D) The temperature is increased.
。 。
4.At 25 C , E cell = 1.47 V for the voltaic cell:
2+ 2+
V (s) | V (1M) || Cu (1M) | Cu (s)
(A)V (s) is the anode.
(B)V (s) is the negative electrode. (正负极我常搞混 ，怎麽简单扼要判断呢?!)
(C)Electrons flow from V (s) to Cu (s).
(D)The cell potential (E cell) of the reaction is zero at equilibrium.
5.Which of the following involve(s) in an increase in the entropy of the
system ?
(A)grinding a large crystal of KCl to powder (这选项的意思，不是很懂@@")
(B)Br (g) -> Br2 (l)
(C)O2(298K) -> O2(373K)
(D)NH3 (1atm , 298K) -> NH3 (3atm , 298K) (这个讲一下好了^^)
(E)mixing benzene with toluene (Both have similar intermolecular forces)
( (E)选项还是无法理解!!)
6.Which of the following statements is(are) true ?
+
(A) O2 would give a bond order of 2.5
(B) C2 is diamagnetic
(C) Six electrons are involved in pi ponding in benzene , C6H6
+ -
(D) N-O bond length NO < NO2
2-
(E) The carbon-carbon bond in C2 is stronger than the one in CH3CH3
7.Which of the following statements related to alkali metals and
alkaline earth metals are incorrect?
(A)Thay can all be obtained via electrolysis of their molten salts.
(B)Their oxides can all be dissolved in the strong acid.
(C)Their carbonate salts are all fairly soluble in water.
(D)Their ions present in water are all colorless and not reactive.
(E)Alkaline earth metals can form compounds of oxidation numbers
2
+1 and +2 , because of the presence of ns electrons in their
outer shells.
(上面这题我一直不知道正解到底是什麽?!XDD")
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 111.249.238.137
1F：→ Carlchen:建议 H大 改改标题 打出年份 方便後人搜寻 07/06 15:55
2F：→ Carlchen:首先，原po问的第一,二题，o810418大 讲解得还不错啊~再 07/06 16:05
3F：→ Carlchen:仔细看看他讲的喔~ 07/06 16:05
4F：推 Carlchen:3.因为不会改变原有气体的压力，所以不影响平衡(不动) 07/06 16:11
5F：→ Carlchen:4.「电子流出」的电极，代表「电流流入」该电极，所以就 07/06 16:17
6F：→ Carlchen:是负极 07/06 16:21
7F：→ Carlchen:5.A.磨成粉墨的意思(S增大) D.加压可以想像gas又更像液体 07/06 16:22
8F：→ Carlchen:了(S减小) E.私下猜溶解(互溶)会使S增大 07/06 16:24
9F：→ Highhuman:thx~ 07/06 16:32
10F：→ Carlchen:7.私下给 C E 07/06 16:34