化學 (科學) | fedest.com

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chem MC

89 Q.30
Magnesium is a stronger oxidizing agent
than sodium.
Mg2+ accepts electrons more readily than
Na+(aq).
1st statement 2nd statement
A. True True 2nd statement is a correct explanation of the 1st one.
B. True True 2nd statement is NOT a correct explanation of the 1st one.
C. True/False False/True Only ONE of the statements is true, the other is false.
D. False False -----

The ans is C but I don't understand
Can anyone explain to me...

2006-10-19 17:37:35 · 2 個解答 · 發問者 2003 2

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關於methane架..??（１０分）

Which of the following statements concerning methane is correct?

A) It burns with a smoky flame in air
B) It does not react with acids
C) It reacts with iodine readily
D) It is a liquid at room temperature and pressure

幫下我呀！！唔該呀～～

2006-10-19 16:04:40 · 2 個解答 · 發問者 ? 1

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N2O3 既英文化學名

N2O3 係咪 dinitrogen trioxide?
定係nitrogen trioxide?

如果係冇”di” 傢話又點解呢?
呢個係covalent bond 泥個啵!

我上網係wikipedia 搵就有”di”
(http://en.wikipedia.org/wiki/Dinitrogen_trioxide)
但係我有好幾個朋友同老師都話係冇”di”

2006-10-19 14:11:56 · 2 個解答 · 發問者 ? 2

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M的算法？～10

要以10ml泡製2M的Tris，請問要加入Tris幾克？
Tris分子量：121～請詳細解說

2006-10-19 12:03:11 · 2 個解答 · 發問者 Anonymous

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化妝品容器充填前需作什麼項目檢驗？

化妝品廠商在使用容器(如軟管或真空瓶)充填內容物前需作什麼項目檢驗？容器清潔該怎麼做？有沒有什麼規定？向什麼單位可以得知相關規定？

2006-10-19 07:07:50 · 2 個解答 · 發問者 james 6

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Ideal Gas Law ; Calculation of one variable

A 2.00-L tank, evacuated and empty, has a mass of 725.6 g. It is filled with butance gas ( C4H10) at 22 celsius to a pressure of 1.78 atm. What is the mass of the tank after it is filled?

Thanks!!

2006-10-19 04:37:37 · 2 個解答 · 發問者 Hiu Tan 1

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關於乳酸菌的一些問題..... 20點~~~

以下的乳酸菌問題..... 給20點~
1.如何培養乳酸菌(溫度器皿水溶液...) 普通培養法
2.生活中何處找的到乳酸菌??
3.晶球優酪乳的發展過程??(哪一牌哪一種都可)
4.自製優格怎樣才算做的好??(有哪些地方注意)
拜託大家了

2006-10-18 21:00:24 · 1 個解答 · 發問者元仔★ 2

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含Ni的電解液

請問大家一個問題
就是有哪些電解液的組成含有Ni呢？
麻煩大家解答了

2006-10-18 19:45:49 · 2 個解答 · 發問者 ? 1

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chem gas equation

a gaseous compound of carbon and hydrogen, in a volume of 300ml at a temperature of 300K and a pressure of 1.200atm, furnishes 1.054g of H20 and 1.930g of CO2 when burned in excess oxygen. Calculate the molecular formula of the hydrocarbon.

i use 300ml =0.3dm3, 300k , 1.200atm and PV=nRT,i can calculate the no. of mole of compound of carbon and hydrogen.then.... i dont know how to calculate the molecular formula?

2006-10-18 19:42:38 · 3 個解答 · 發問者 ? 1

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請問一下什麼是電極面積？最近要作科展，有些名詞搞不懂。

請問一下各位大大～
因為最近要作科展，可是我搞不懂一些專有名詞（因為還沒教到）
1.電阻
2.電壓
3.電極面積
就先大概這些，想到時我會在補充問題的！謝謝各位大大！

2006-10-18 19:36:33 · 2 個解答 · 發問者 Anonymous

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冰醋酸和電石氣是純淨物定混和物

冰醋酸化學式是什麼?
是純淨物定混和物?
電石氣化學式是什麼?
是純淨物定混和物?

2006-10-18 18:39:19 · 2 個解答 · 發問者 ? 1

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KMnO4,K2Cr2O7/H+

點解...
KMnO4,K2Cr2O7要acidified?

係用咩acid黎acidified?

2006-10-18 17:38:13 · 5 個解答 · 發問者 2003 2

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哪個會易揮發

我想問starch , iodine solution同iodide 哪個會易揮發？
又或是個個都唔易揮發呢？

做iodometric titration時點解唔可以一早落iodine落去？

2006-10-18 17:18:02 · 1 個解答 · 發問者榮綿 2

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Chem.Question--- Compound and Mixture

What is meant by " Compound " and "Mixture"?
What are their differences ?

2006-10-18 14:35:06 · 3 個解答 · 發問者 J 7

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化學原子結構．．．要詳細

描述26 12mg原子的結構。

2006-10-18 11:47:47 · 1 個解答 · 發問者 wai tung 1

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可讓螺釘類五金件耐鏽蝕達鹽霧96小時以上表面處理方式?

請問各位大大:有無特殊電鍍或表面處理方式,可讓五金零件經的起更久的鏽蝕考驗!嚴格來說是鹽霧測試96小時以上.希望不吝指教,感激不盡

2006-10-18 09:02:33 · 2 個解答 · 發問者 jjj 1

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有關放熱反應的問題

我想請問有咩因素決定一個化學反應是否放熱反應?

2006-10-17 19:11:14 · 2 個解答 · 發問者 chauling 1

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ｃhem - Fehling's and Tollen's reagent

用 Fehling's reagent 和 Tollen's reagent 測試乙醛 (Ethanal)、甲醛 (Methanal) 、苯醛 (Benzaldehyde)、丙酮(Propanone) 會有什麼結果 ?
還有 Fehling's reagent 究竟是什麼東西 ? 它的原理的什麼 ?

2006-10-17 18:46:12 · 2 個解答 · 發問者 Yanni Wong 1

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有冇人知sulphamic acid + NaOH ge equation 係咩呀?????

sulohamic acid + sodium hydroxide 的equation係咩呀?????

NH2SO3H + NaOH

有冇人知呀....?????

2006-10-17 18:27:54 · 2 個解答 · 發問者 Anonymous

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空氣污染防治

設某一都市之總固體落地量每日為800mg/m2，若該市面積為15KM*20KM，則一年降落於該城市之粒狀物總量有多少？
mg(ㄇㄩㄣ)(毫克)
m2(m二次方)

2006-10-17 15:48:00 · 1 個解答 · 發問者 ? 1

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chem MC

86. Q.6
aCl2 + 6OH - → bCl - + ClO3- + 3H2O
When the above equation is balanced, the values for a and b should be:
a b
A. 1 1
B. 2 3
C. 3 5
D. 4 7

The answer is C
It seems that all ans suit the equation
but I don't understand why C is the answer.
Can anyone explain to me?

Thank you very much.

2006-10-17 14:48:26 · 2 個解答 · 發問者 2003 2

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acidified KMnO4,K2Cr2O7

點解...
KMnO4,K2Cr2O7要acidified?

2006-10-17 14:06:49 · 1 個解答 · 發問者 2003 2

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在HPLC的分析圖譜中,PEAK分叉的原因有哪些呢?20點喔

因為最近在打HPLC(高效能液相層析儀)時,發現我的標準品的 PEAK有分叉的情形,而不是單獨的一根!!!我想請問化學達人們:一般在HPLC的分析圖譜中,PEAK分叉的原因有哪些呢?該如何解決或避免此一問題呢?

2006-10-17 12:54:40 · 4 個解答 · 發問者 Anonymous

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化學的問提 (還滿難的)

A student collected the following data for the calorimeter constant experiment :
Volume of cold water: 4.73 mL
Temperature of cold water: 9.1 °C
Volume of hot water: 7.44 mL
Temperature of hot water: 50.1 °C
Final temperature after mixing: 26.7 °C

Use this data to determine the calorimeter constant (Ccal) to three significant figures.

Assume the specific heat is 4.184 J g-1 °C-1 for both cold and hot water. Also assume the density of water is 1.00 g/mL for the hot and cold water.

2006-10-17 08:48:42 · 1 個解答 · 發問者 pp 2

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