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发表于 16-3-2011 08:41 AM
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sorry ya...the explanation of ans D got mistake...there is no related to ions...(long time ...
silent91 发表于 15-3-2011 03:16 PM 
ok..thanks so much..i ll post other questions here next time since tis is the only place for answering my questions..haha |
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发表于 17-3-2011 08:42 PM
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ok..thanks so much..i ll post other questions here next time since tis is the only place fo ...
破晓时分 发表于 16-3-2011 08:41 AM 
因为以前，我也是靠这里的senior指点的。所以我尽力咯 |
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发表于 18-3-2011 09:33 AM
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因为以前，我也是靠这里的senior指点的。所以我尽力咯
silent91 发表于 17-3-2011 08:42 PM
毕业了？stpm考得怎样？ |
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发表于 18-3-2011 05:42 PM
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请有谁有pass year的题目，2006-2010
不要叫我找longman的，因为longman 只有到2004年而已 |
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发表于 18-3-2011 09:29 PM
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毕业了？stpm考得怎样？
破晓时分 发表于 18-3-2011 09:33 AM
中等咯。有过三 |
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发表于 31-3-2011 01:05 PM
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发表于 1-4-2011 08:35 PM
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Chemistry 买那一种参考书读比较好？介绍介绍咧
我去Popular找不到书的， Ace Ahead(oxford) 的只有 Vol ...
huatiang 发表于 31-3-2011 01:05 PM
其实longman已经够了的.如果你觉得不够,可以去找tan yin toon写的, 但是只有phy chem 和 organic chem.
是很厚一下的,注意,部分内容已经不是考试范围!!! |
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发表于 12-4-2011 12:52 PM
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这里有些问题..麻烦下了...
CHAPTER 4 : ELECTRONIC STRUCTURE OF ATOMS
1. What is the number of lines which can be obtained for the Lyman and Balmer series involving the first seven energy levels in the emission spectrum for the hydrogen atom.?
Lyman Balmer
A. 3 2
B 4 3
C 5 4
D 6 5
2. The emission spectrum of the hydrogen atom is a line spectrum because
A. The energy of the electron in the hydrogen atom is quantized
B the electron can only be at certain allowable energy levels.
C. the electron transition involves the electron dropping from a higher energy levels to a lower energy level.
3. What is the maximum number of emission lines tat can be formed for the hydrogen atom with the energy levels n=1, n=2, n=3 and n=4?
A. 3
B. 4
C. 5
D. 6
4. What is the maximum number of emission lnes tat can be formed from the electron transtitions involving the first five energy levels..?
A 5
B 8
C 10
D 15
Wish there are answer as well as explanation…谢谢.. |
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发表于 12-4-2011 09:15 PM
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这里有些问题..麻烦下了...
CHAPTER 4 : ELECTRONIC STRUCTURE OF ATOMS
1. What is the number of l ...
破晓时分 发表于 12-4-2011 12:52 PM
1. D 画七个energy level,from n=1 到 n=7.
Lyman 开始是从 n=2 到 n=1, n=3到n=1...如此类推...
2. 应该是C (太久了,不是很记得)
3. 如第一题,画energy level了先, 然后就从lyman series开始画.
然后就balmer...etc...最后是 n=4 --------> n=3
再不明白就看我献丑.
n=2 ------> n=1
n=3 -------> n=1
n=4--------> n=1
n=3 -------> n=2
n=4--------> n=2
n=4--------> n=3
所以总共是6条线.
4.做法如第三.
*有错请纠正... |
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发表于 13-4-2011 04:58 PM
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发表于 13-4-2011 09:02 PM
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谢谢，我懂答案了..今天问了老师....可是第二题的答案是B..at a certain energy level..（书本后面 ...
破晓时分 发表于 13-4-2011 04:58 PM
第二题,如果你有tan yin toon那本的话,应该会有答案的....
我自己是懒惰去翻书了.... |
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发表于 14-4-2011 02:06 PM
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第二题,如果你有tan yin toon那本的话,应该会有答案的....
我自己是懒惰去翻书了....
silent91 发表于 13-4-2011 09:02 PM
我就是读tanyin toon写的oxford fajar的chemis..这题就是里面的问题...哈哈..thanks |
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发表于 14-4-2011 09:56 PM
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Physical Chemistry 第一课的 mass spectrum 的 isotope(peak at M+1) 是什么来的？
我看不懂，谁能解释一下，谢谢。 |
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发表于 17-4-2011 02:59 PM
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发表于 18-4-2011 09:33 PM
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谁能帮帮我解决这个问题
其实我问什么我自己也不太明白，
因为我不知道怎样问= =
照着这课的那一 ...
huatiang 发表于 17-4-2011 02:59 PM
完全不明白你问什么,介意说是那一本书吗? |
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发表于 18-4-2011 09:52 PM
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Ace Ahead 的 Chemistry,第11面。我不太懂。 |
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发表于 18-4-2011 11:35 PM
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1.26g of an alkene W reacts with chlorine to form 3.39g of a dichloroalkane,X. What is the molecular formula of X?
能解释如何做吗??
希望senior们多多指教~ |
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发表于 19-4-2011 08:20 PM
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Ace Ahead 的 Chemistry,第11面。我不太懂。
huatiang 发表于 18-4-2011 09:52 PM
paiseh,没有那本书,帮不到你 |
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发表于 21-4-2011 11:22 PM
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回复 777# sky23
increase in mass is due to chlorine.
so the chlorine that added to the molecules shud b 3.39-1.26=2.13
give intial is an alkene.so 1 molecule alkene react wit 2 cl2 atom to form final product.so no of mole of cl2 used = no of mole of alkene react
2.13/35.5 =.06 mole cl atom , / 0.03 mole cl2 molecules.since 0.03 mole oso no of mole of alkene used , then rmm of alkene = 1.26 /.03=42
since rmm is 42 , then the alkene shud b propene.
不懂对吗。半年没有动化学了 |
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发表于 22-4-2011 04:14 PM
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