化學

even if there is no experimental error, explain why the graphs plotted cannot be an absolute straight line.

2007-02-16 05:47:57 · 1 個解答 · 發問者 bowieyue2004 2

我是要做專題研究
想做出有透明感覺得肥皂.......
看起來就像果棟一樣 ~ ~ ~ ~ ~ ~
但我是過很多次.......
做出來都沒成功 ~_~//
不知是哪出問題??
請各位大大
幫幫我
提供一些做過的經驗或技巧
謝謝喔!!!

2007-02-15 19:10:50 · 2 個解答 · 發問者 風 1

i want to ask Cu and CuO when add con.H2SO4時係米會both都會出SO2
ans in eng plz thx
Also if add con.HCL係米可以分辨到Cu and CuO?

2007-02-15 17:22:06 · 5 個解答 · 發問者 ? 1

請問在台南高雄地區..
哪些地方有賣透析膜?
可以的話可附上電話和公司名稱或地址嗎?
謝謝

2007-02-15 09:58:48 · 1 個解答 · 發問者 幸福是一顆夢想的種子 3

香港電燈公司和中華電力有限公司分別使用哪種化右燃料來發電?

2007-02-15 07:12:27 · 2 個解答 · 發問者 Emmy 1

生活環境中有哪些事物現象與化學有關，但你無法加以解釋，請條列。

2007-02-15 04:00:09 · 1 個解答 · 發問者 Xing Ni 2

如題,想要買這本書(6th edition)自修,請提供詳細資料,或者是願意割愛亦可,謝謝回答...

2007-02-14 19:20:52 · 1 個解答 · 發問者 ? 1

The reaction between methane and oxygen gas is according to the following equation
CH4(g)+2O2-->CO2+2H2O
When 10cm³ of methane gas is burnt in 50cm³,the volume of gases is
[All the volumes are measured at 100 oC and atmospheric pressure]

The ans:60cm³

2007-02-14 17:09:26 · 1 個解答 · 發問者 2003 2

水ㄉ成分裡有營養素那那些營養素從哪裡來?
那又含些什麼??
(請解釋清楚謝謝!!)

2007-02-14 16:22:28 · 2 個解答 · 發問者 牙 2

When SO2 is bubbled into a beaker of acidified K2Cr2O7 solution,which of the following statements about the reaction is correct?

A. SO2 bleaches acidifed K2Cr2O7
Why this is wrong?

B.The oxidation number of Chromium changes from +6 to+2

C.The colour of the solution turns green
Why this is wrong?

D. SO2 is oxidized
SO2唔會變左SO3-2先,一次過到SO42-?

ans:D

2007-02-14 16:10:25 · 2 個解答 · 發問者 2003 2

Chlorine bleach can be reduced by dilute HCI to form CI2

Why this statement is wrong?

OCI- + CI- + 2H+ --> CI2 + H2O

oxidation no. of CI in CI = +1

oxidation no. of CI in CI2 = 0

Why this is wrong?

by the way, chlorine bleach can be said as oxidizing agent?

2007-02-14 16:09:55 · 1 個解答 · 發問者 2003 2

Fe係oxidize 到2+定3+?
如不可的話,
用乜野先到3+?

2007-02-14 15:26:52 · 3 個解答 · 發問者 2003 2

Ca(OH)2 + CI2 就出CaCI2,Ca(OCI)2,H2O
KOH+CI2就出KCI,KCIO3+H2O

1.可唔可以介紹CIO3-呢隻野,咩名,特性,用途之類....?

2.點解係出CIO3-?
幾時出CIO3,幾時出OCI-?
同加咩metal hydroxide有關?

3.點解第二條式oxidation number of oxygen 冇變?
oxidation no. of O in KOH =-2
-1+3x=-1
oxidation no. of O in CIO3-=0 ?
我計錯左?

2007-02-14 15:25:47 · 1 個解答 · 發問者 2003 2

1. some blue vitriol, CuSO4.5H2O, was heated to constant mass at about 120 degree C, and then at a hogher temp., with results as below:
mass of crucible: 10.00g
mass of crucible+blue vitriol: 14.98g
mass of crucible+ residue (120 degree C): 13.54g
mass of crucible+ residue (higher temp): 13.18g
what stage of dehydration is reached at each of the two temp.?

2007-02-14 13:10:17 · 1 個解答 · 發問者 kit 4

1下列哪種物質具有最低的沸點?
A.乙醇
B.丙-1-醇
C.丙烷
D.丁烷

2離子化合物X的化學式是AB2(2字是下標的)的A和B分別代表陽離子和陰離子。若A和B具有相同
的電子排佈，X可能是
A.硫化鉀
B.氟化鎂
C.二氧化硅
D.溴化鈣

3.X是週期表內第VI族的元素。X可生成X2-離子。下列的陳述，哪些正確?
(1)生成X2-離子時，X的氧化數減少。
(2)X原子和X2-離子均有相同的電子層數目。
(3)X原子和X2-離子均有相同的核電荷。
A.只有(1)和(2)
B.只有(1)和(3)
C.只有(2)和(3)
D.(1)、(2)、(3)

4.某壓縮氣筒貼有易燃的危險警告標籤，該氣筒可能盛載下列哪種氣體？
A.氫
B.氧
C.氯
D.氬

2007-02-14 12:27:30 · 3 個解答 · 發問者 secret 2

我有一白金礦來源經EDS定性分析確定有鉑元素,ICP定量確定含量為11%-14%請問要如何提練或是台灣誰能提煉製95%以上

2007-02-14 08:20:16 · 4 個解答 · 發問者 ? 3

Joe has closed all the windows of his car and parked his car under the Sun for three hours .
a ) When he opens a car door , he fells that the car inside is very hot . Explain briely why the car inside gets hot .
b ) Some drivers use a shiny shield to reduce the temperature rise in their cars . Explain briefly how it works .

2007-02-14 07:39:16 · 1 個解答 · 發問者 怡文 1

已知 4NH3(g) + 3O2(g) ------> 2N2(g) + 6H2O(l) delta H = -1536 kJ

N2O(g) + H2(g) -------> N2(g) + H2O(l) delta H = -367.4 kJ

H2(g) + 1/2 O2(g) -------> H2O delta H = -285.9 kJ

利用以上條件求出 2NH3(g) + 3N2O ------> 4N2(g) + 3H2O之delta H = ?

P.S. 我計算到的答案是 -1010kJ ,不知道是否正確呢?

2007-02-13 16:47:27 · 2 個解答 · 發問者 Anonymous

發現鉛的人是誰...

鉛有什麼歷史....

鉛在工業上又有什麼用途...

在生活上還有什麼應用...

2007-02-13 15:49:04 · 2 個解答 · 發問者 林 1

except destorying the ozone layer,what are the other problems of using large amount of expanded polystrene?

explain why the destruction of ozone layer will cause harmful effects to human being

2007-02-13 13:49:44 · 1 個解答 · 發問者 Kin Yung 1

potassium manganate(VII), hydrogen peroxide are reacting in a conical flask. At different time intervals, 10cm3 of reaction mixture is withdrawn, add to conical flask with 10cm3 H2SO4(stopwatch is started at this instant) and is then titrated with dilute K2MnO4 solution.

1. write a balance chemical equation to show the reaction between hydrogen peroxide and potassium permanganate.

2. what is the use of the manganese(IV)oxide?

2007-02-13 11:52:36 · 1 個解答 · 發問者 ? 2

想問吓
1.NaOH(s)-->NaOH(aq)
2.HCI(g)-->HCI(aq)
點解第一個果個係physical change,第二果個係chemical change...?
大家都係就冇water變ions傘,可唔可以講吓有咩分別?

2007-02-12 19:38:42 · 2 個解答 · 發問者 2003 2

既然光 (hv) 可以break Cl to Cl single bond 去做 radical, 點解係正常狀態下Chlorine是diatomic molecule 而不是一堆radical 呢...?

2007-02-12 16:43:48 · 2 個解答 · 發問者 ? 3

acid base reaction occur in non-aqueous solution

i forget it ~ thx~

2007-02-12 15:00:16 · 1 個解答 · 發問者 YA! HOO! 2

dissociate,ionize呢兩個字有乜分別?

2007-02-12 14:04:22 · 1 個解答 · 發問者 2003 2

http://funmovman.blogspot.com/2007/02/blog-post.html

睇下大家~ 用蠟燭發電?
咩原理??

2007-02-12 10:31:34 · 2 個解答 · 發問者 KinSan 1

我最近要做個實驗，就是要做氫氧燃料電池，不過我有幾個問題想要問大家

1.乾電池裡的二氧化錳和氯化銨液體對人體或其他東西有沒有害?

2.汽車會用到電池嗎?是什麼電池?

3.電池有分幾種?(不用告訴我詳細介紹)

2007-02-12 05:59:12 · 2 個解答 · 發問者 Darren 5

電池不是活性大，容易失去電子的電極當負極嗎?
那為什麼"碳鋅電池"正極是活性較大的碳棒?

2007-02-12 03:18:08 · 2 個解答 · 發問者 啾啾梨 4

100 μl l-1
是濃度的單位嗎?
那中文該怎麼說?

謝謝賜教.

2007-02-11 16:25:23 · 2 個解答 · 發問者 宅男な逆襲 6

點解acid 係form covalent bond,例如HCI(aq),點解H係positve,CI係negative,如果佢地係covalent bond,即係sharing electrons啦,H又冇少左一個electron,點解佢會變左H+?

定係當HCI dissolve左許water之後,CI就會"搶"左H果粒electron?

2007-02-11 15:56:21 · 1 個解答 · 發問者 2003 2