化学交流区

TonyDaisie

请所有化学系的同学或有兴趣的人有进来聊聊, 功课也好, 问题也好, 什么都好, 大家来点空中交流吧！！

[ 本帖最后由 微中子 于 3-1-2008 09:02 AM 编辑 ]

kensai

谢谢你的热诚，不过还是要更你讲，科学论坛是cari最不活跃和最少帖子的论坛，平均每天回复帖子数量不会超过5个，有时3，4天都不会有人回复。

所以不要抱太大希望有人会来交流

不过你有任何问题可以post上来，我会尽量帮你

jiko

不是我们不要回复啦!
因为啊,在这里出现的都是高难度的问题,那些问题又不能随便带过的!
像我这样半桶水的人怎么好意思胡乱回复啊???

TonyDaisie

有问题的话尽量拿出来发问。大家可以互相讨论。真的希望可以交到对化学有兴趣的朋友。

kbubble

我对化学也有兴趣,但化学还需要加强.
这此期中考还不及格

mc_tablo

修化学的朋友们，你们都有修unit process这科吗？
因为有很多关于这一科的计算问题要请教。

我想問。。。要怎樣才能制造出一灌沐育露。。。。。？我女友生日要到了。。。

我想要親手制造一灌沐育露送給她。。。。。（我不是買不起），而是要親手制造

的會比較有（心意）。。。我只知道須要用化學品。。。可是我不知道還要加什么

物質和要怎樣參這些東西。。。？大家幫幫我好嗎。。。？

kensai

原帖由 亦正亦邪 于 16-5-2006 11:11 PM 发表
我想問。。。要怎樣才能制造出一灌沐育露。。。。。？我女友生日要到了。。。

我想要親手制造一灌沐育露送給她。。。。。（我不是買不起），而是要親手制造

的會比較有（心意）。。。我只知道須要用化學品。 ...

亲手做的会很差，
只可以看到一点点的泡泡而已，不能用来做清洗作用
而且味道也不是很好闻，如果要加味道会有点麻烦，

不如试下做音乐盒罢，哈哈
更加有纪念价值。

灰羊

明天考化學
無機讀到很死...
一大堆化學反應....

i am lower 6 student this year(2006) i have a question to ask your....
what is D negatif up?

i am here got one question
RAM of Cu = 63.55 if Cu consists of atom with nucleon no. 63 and 65, calculate the% composition of the isotope of Cu.

have you all anyone got a web site to learn chemistry?

kensai

原帖由 ~ciyun~ 于 18-5-2006 08:05 PM 发表
i am lower 6 student this year(2006) i have a question to ask your....
what is D negatif up?

i am here got one question
RAM of Cu = 63.55 if Cu consists of atom with nucleon no. 63 and 65, cal ...

solve
63X + 65(1-X) = 63.55
X = 0.725
so, % of Cu-63 = 72.5 %

% of Cu-65 = (1-0.725) x 100%
= 27.5%

hellodizzy

各位可以介绍以下中六的化学参考书吗？

^Li_Ling^

请问这里有谁是Form 4的??
我想请问Chemistry应该买哪个出版社的书呢??
哪一本才好呢??
请大家给我一些意见..
谢谢你们!!

hellodizzy

原帖由 亦正亦邪 于 16-5-2006 11:11 PM 发表
我想問。。。要怎樣才能制造出一灌沐育露。。。。。？我女友生日要到了。。。

我想要親手制造一灌沐育露送給她。。。。。（我不是買不起），而是要親手制造

的會比較有（心意）。。。我只知道須要用化學品。 ...

我 只 做 过 肥 皂 而 已， 没 做 过 沐 浴 露

原帖由 kensai 于 18/5/2006 20:45 发表


solve
63X + 65(1-X) = 63.55
X = 0.725
so, % of Cu-63 = 72.5 %

% of Cu-65 = (1-0.725) x 100%
= 27.5%

thx how about this
a sample of 0.025mol of the chloride of an element Z was dissolved in distilled water and the solution made up to 500 cube cm .25 cube cm of this solution reacted with 25 cube cm of 0.1 mol negatif cube dm silver nitrate solution. what is the most lokely formula of the chloride.

kensai

原帖由 ~ciyun~ 于 20-5-2006 04:40 PM 发表

thx how about this
a sample of 0.025mol of the chloride of an element Z was dissolved in distilled water and the solution made up to 500 cube cm .25 cube cm of this solution reacted with 25 cub ...

Ag+ Cl -> AgCl

no of mol of Ag= 0.1 x 0.025 = 0.0025

since 1 mol Ag reacts with 1 mol Cl,

no of mol of Cl in 25 cm cube = 0.0025

no of mol of Cl in 500 cm cube = 0.0025 x 500/25= 0.05 mol

0.025 mol of Z compound gives 0.05 mol of Cl
so,1 mol of Z compound gives 2 mol of Cl

Thus, formula of Z compound = ZCl2

原帖由 kensai 于 20/5/2006 19:56 发表



Ag+ Cl -> AgCl

no of mol of Ag= 0.1 x 0.025 = 0.0025

since 1 mol Ag reacts with 1 mol Cl,

no of mol of Cl in 25 cm cube = 0.0025

no of mol of Cl in 500 cm cube = 0.0025 x 500/ ...

thx..
a mixture of 50 cm cube of oxygen and 10 cm cube of hydrogen is ignited continuously. what is the maximum theoretical decrease in volume?Al gas volume are recorded at 293K and standard atmospheric.
what the answer?
what is 293K?

kensai

原帖由 ~ciyun~ 于 20-5-2006 08:56 PM 发表


thx..
a mixture of 50 cm cube of oxygen and 10 cm cube of hydrogen is ignited continuously. what is the maximum theoretical decrease in volume?Al gas volume are recorded at 293K and standard a ...

let x mole of hydrogen occupies 10 cm cube ,
so 5x occupies 50 cm cube

O2 + 2H2 -> 2H2O

X mol of hydrogen reacts with X/2 mol of oxygen to form X mol of water,
thus 5X - X/2 mol = 4.5 mol of Oxygen is in excess,


Total mole before reaction = 6X
Total mole after reaction = 4.5X   (assume water H20 is not included)
reduction in volume = 1.5X

since X mol occupies 10 cm cube,
so 1.5X mol occupies 15 cm cube


这里是assume water is in liquid ( 因为 standard atm 和 温度）
如果是water vapour 的话， 就加 x mol ( 10cm cube)
total reduction = 0.5 mol / 5 cm cube
293k 是温度 ， 20 degree celsius

[ 本帖最后由 kensai 于 20-5-2006 09:17 PM 编辑 ]

原帖由 kensai 于 20/5/2006 21:13 发表



let x mole of hydrogen occupies 10 cm cube ,
so 5x occupies 50 cm cube

O2 + 2H2 -> 2H2O

X mol of hydrogen reacts with X/2 mol of oxygen to form X mol of water,
thus 5X - X/2 mol = ...

谢谢你。不过我有些不明白咯！let x mole of hydrogen occupies 10 cm cube ,
so 5x occupies 50 cm cube
是要表使甚没？
还有这几题。
1)12.4g of hydrated sodium thiosulphate, NA2S2O3.5H2O(Mr=248),were dissolved in water and the solution made up to 1 dm cube. what was the concentration of the solution with respect to the sodium ions?
2)when potassium chlorate(V) is heated strongly,it decomposes into potassium chlorate(VII),KCLO4,and potassium chlorate. what is the maximum number of moles of potassium chlorate(VII) which could be produced from 0.2 mol of potassium chlorate(V)?
3)At r.t.p.2.8 dm cube of hydrogen sulphide was mixed with 1.6dm cube of sulhur was mixed with 1.6dm cube sulphur dioxide when the following reaction occured:
2H2S(g)+SO2(g)-->2H2O_3S(s)
what was the total volume of gas remaining after the reaction?
this question need use this 24 dm cube de mah?
4)100dm cube of pollution air is passed through aqueous calcium hydroxide so that all the carbon dioxide present is precipitated as calcium carbonate. the mass of calcium carbonate formed is 0.5g. What is the percentage, by volume,of carbondioxde in the air sample? [C=12;O=16;Ca=40;1 mole of gas under experimental conditions has a volume of 24dm cube]
5)when 20cm cube of a gaseous hydrocarbon were completely burnt in an excess of oxygen.60cam cube of carbon dioxide and 40 cm cube of water vapour were formed, all volumes being meansured at the same tempareture and pressure. what is the formula of the hydrocarbon?

sorry make u busy to teach me how to do thx....

kensai

原帖由 ~ciyun~ 于 20-5-2006 10:21 PM 发表

谢谢你。不过我有些不明白咯！let x mole of hydrogen occupies 10 cm cube ,
so 5x occupies 50 cm cube
是要表使甚没？
还有这几题。
1)12.4g of hydrated sodium thiosulphate, NA2S2O3.5H2O(Mr=248),we ...

这个只不过是数学上的 algreba 罢了，

因为我不知道 10cm cube 的 gas 里面有 多少mol的gas,
所以我就当作 10 cm cube 里面有 x mol,hydrogen 有 x mol
那么 50 cm cube 里面就有 5x mol 了，oxygen 有 5x mol

当然如果你要算的话可以用 pv=nrt 这个formula ,
不过你们老师因该还没有教，所以其实用不用formula 都可以找到答案。