化學

是這樣的
上次老師要我們做葉子的書籤
其步驟中有種鹼性的顆粒(不知叫什麼)
那種顆粒要到哪裡去買？

2006-12-11 14:58:02 · 2 個解答 · 發問者 Anonymous

一個純的金幣含有0.145 mol
求硬幣質量為多少
須計算過程

2006-12-11 07:59:59 · 1 個解答 · 發問者 ? 6

關於nernst equation,
中間個符號係加定減 ?
因為cclee本書話係減,
但hkale個2007個syllabus話係加, 咁應該係邊個先岩@@?
請指教, 謝謝

2006-12-11 06:42:36 · 1 個解答 · 發問者 ? 2

請問在做萃取實驗時，該如何區別液體上層液和下層液是何物質?
及用乙醚作萃取溶劑有何缺點和優點呢??



請知道的人幫我解答一下!!如果答案不確定.是用猜的...麻煩請讓知道的人回答!!謝謝!!

2006-12-10 18:46:17 · 4 個解答 · 發問者 一禪種苗園 2

想問一下1ppm等於多少mg/l啊?那500ppm是轉換成多少mg/l?

2006-12-10 18:00:14 · 4 個解答 · 發問者 Anonymous

pure acid 係指冇水的acid
好似HCl(g)咁
dissolve 落water先有H+

咁其實
SO2
NO2
係咪都可以叫做pure acid?

2006-12-10 16:58:34 · 2 個解答 · 發問者 2003 2

如題。

謝幫幫忙。

2006-12-10 13:48:38 · 1 個解答 · 發問者 Sken 3

Explain the following:
a)Steel hot water tanks often have a bar of magnesium suspended in the water.

b)A battered tin car rust more quickly than a damaged galvanized iron rubbish bin.

2006-12-10 09:58:09 · 1 個解答 · 發問者 kiko 2

您好，有幾個化學發面的問題想要詢問您：

1.請問要如何從中文來判斷他的化學式？
只有死背嗎？
例如：
(1)Cao(石灰)
(2)Na2Co3(蘇打)

想請您幫忙回答以下問題：(可以點選網址)
[化學] [20]請問背化學式是否有技巧？
http://tw.knowledge.yahoo.com/question/question?qid=1106120408488

2.請問數個化學式的中文：
(1)Ca(HCo3)2
(2) Mg(HCo3)2
(3)CaCo3
(4)MgCo3
(5)Ca(OH2)
(6)No3-
(7)So42-
(8)Po43-
(9)化學需氧量用的東西：K2Cr2O7
謝謝

2006-12-10 09:41:57 · 1 個解答 · 發問者 Y24743562309 6

好得意wor!

點解low density polythene要用200 oC同埋high pressure去整拒但係high density polythene會係用60 oC同埋low pressure去搞拒既呢?

唔係應該arm arm調番轉咩...@@

2006-12-09 21:12:21 · 2 個解答 · 發問者 Emily Yeung 2

CuSO4 + KI + Na2S2O3
反應後生成ge白色物質係咩ar?
好想知ar,問同學同師兄師姐都話唔係甘識,但我真係好想知ar!!!
唔該你地識ge話話俾我知ar,唔該晒~

2006-12-09 14:50:37 · 2 個解答 · 發問者 Anonymous

li個係咩圖尼嫁?

http://img208.imageshack.us/my.php?image=5486ob2.png

我係喺一個化學工具(CHEMIX)見到既!

係咩尼?

2006-12-09 12:44:40 · 1 個解答 · 發問者 winghim 3

係咪所有alkanoic acid 都係monobasic?

2006-12-09 12:19:35 · 2 個解答 · 發問者 2003 2

1.pure acid 係咪即係話一個acid 冇水?

2.係咪
pure acid 就係 covalent bond
impure acid 就係ionic bond?
explain

2006-12-09 11:38:10 · 1 個解答 · 發問者 2003 2

詳細解釋...

2006-12-09 09:27:56 · 1 個解答 · 發問者 kint 1

除了水外還有什麼日常用品可以電解?

2006-12-09 07:42:49 · 2 個解答 · 發問者 ? 3

I want to ask what's the different between current and voltage?
(Please answer in short and easy to follow way)

2006-12-09 07:10:18 · 2 個解答 · 發問者 sai 2

1.Measure 10 cm3 of ethyl ethanoate into an insulated 50 cm3 breaker. Record its temperature.
2.Add to this 10 cm3 of trichloromethane and mix well. Record the highest temperature of the liquid.
using either one liquid in excess. Form the temperature change estimate the strength of hydrogen bond formed between molecules of ethyl ethanoate and trichloromethane

Explain why it does not matter which liquid is used in excess?

2006-12-08 20:08:27 · 1 個解答 · 發問者 MACY 1

1.Using a measuring cylinder, add 10 cm3 of ethanol into an insulated 50 cm3 breaker. Measure the temperature of the liquid.
2.add 20 cm3 of cyclohexane to the ethanol in the breaker, mix well and record the lowest temperature of the liquid
Explain why cyclohexane has to be used in excess in this experiment
Comment on the reliability of the hydrogen bond strength obtained.

2006-12-08 20:05:52 · 1 個解答 · 發問者 MACY 1

順式脂肪酸和反式脂肪酸ㄉ順反是指順反異構物咩????

知道滴人教教我唄~~~

2006-12-08 16:17:16 · 1 個解答 · 發問者 Anonymous

8.Why mustn't objects of the same volume volume have the same mass?

(a) Why do some matters float, but some sink in fluid?

(Write down your answer to question 8(a) and please answer the question completely and clearly.)

Thanks a lot for answer my question.

2006-12-08 15:35:59 · 2 個解答 · 發問者 Edward 1

1. Which object can float in water(density=1.0g/cm3) ?
a.Object X of mass 0.9g
b.Object Y of mass 1.1g
c.Object Z of mass 1.3g
d.Cannot be determined

2.Which object can float in water(density=1.0g/cm3) ?
a.Object R of volume 0.9cm3
b.Object S of volume 1.1cm3
c.Object T of volume 1.3cm3
d.Cannot be determined

2006-12-08 15:25:32 · 1 個解答 · 發問者 Edward 1

實驗過程: 取ㄧ試管加入2克二氧化錳((秤重))在加入1.5克ㄉ綠酸鉀~以酒精燈燃燒制二氧化錳變成液體釋放出氧氣~點燃ㄧ線香燃燒試管內ㄉ氧氣~將氧氣全部燃燒殆盡~在秤其重量~

問: 本實驗中若氯酸鉀沒有完全分解，為實驗誤差原因所在，此種誤差對所求含氧重量百分率有何影響?

2006-12-08 15:22:52 · 2 個解答 · 發問者 涵 1

metal can conduct electricity due to presence of free electrons but carbon should have no free electron in its structure.Why it can conduct electricity?

2006-12-08 13:45:44 · 2 個解答 · 發問者 2003 2

transition metal係咩?

2006-12-08 13:44:48 · 2 個解答 · 發問者 2003 2

麻煩知道的人救命一下
我想確定楊梅有沒有淨水場(不是污水處理廠喔!!)
淨水場不是污水處理廠...不一樣

2006-12-08 13:15:46 · 3 個解答 · 發問者 ? 4

關於燃點酒精一問
之前聽人說,隻手放在燃點後的酒精是沒事
是不是的?為什麼?

2006-12-08 12:49:22 · 3 個解答 · 發問者 Xin 3

點解會有reaction?邊個搶邊個的e-?點解會咁?

2006-12-08 12:38:44 · 1 個解答 · 發問者 LeeHon Lam 1

我想問問個定義
compound and molecule的分別??


molecule係咪當兩個element以covalent bond相連的product就叫molecule
compound係咪當兩個element以ionic bond相連的product就叫compound

so 有冇ionic molecule and covalent compound
如有,咁應該係點樣準確地為compound and molecule定義?


另外,鹽的定義又係咩呢
所有金屬+非金屬的化合物都叫鹽麼?
咁all ionic compound都叫鹽,對嗎

謝~

2006-12-08 06:32:21 · 3 個解答 · 發問者 Ng 1

100ml溶液含CH3COOH 0.10M 和 CH3COONa 0.10M, 求pH?
CH3COOH: Ka = 1.8 x 10^ - 5

2006-12-08 04:29:24 · 2 個解答 · 發問者 Anonymous