科學 - 四月 2007

metal hydroxide+SO2/CO2
1.係咪任何metal hydroxide都同SO2/CO2有reaction?
定係Na,K,Ca only?

2.metal hydroxide+SO2/CO2一定出XXHCO3/XXHSO3先?
如果NaOH in excess
係咪同SO2 react 就出NaHSO3,再出NaSO3?

2007-04-10 13:43:41 · 1 個解答 · 發問者 2003 2 in 化學

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泵浦的能力中, churn pressure如何翻譯呢

各位先進:
泵浦的能力中, churn pressure如何翻譯呢
這個測試, 是將泵浦出水口的閥關閉, 來測試流量為0時, 泵浦的壓力

2007-04-10 13:37:18 · 4 個解答 · 發問者期指亂亂來 6 in 工程學

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Pt900的鉑金

鉑金首飾通常含有90%的純鉑金，並被打上“Pt900”的標誌, 那剩下的10%是甚麼成份呢?
鉑金戒台師傅在鑲鑽的過成中,戒台一定會被工具傷到, 請問鑲完鑽後會再鍍上甚麼金屬? 京華鑽石跟我說會鍍上"銠"...一般都是鍍銠嗎?

2007-04-10 12:50:38 · 1 個解答 · 發問者 mimi 1 in 化學

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成分元素？

請問乜野是成分元素？

2007-04-10 12:38:30 · 1 個解答 · 發問者 Snow 1 in 化學

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化學方程式????

發粉含有固體的酸和碳酸氫鈉。人們製造麵包和蛋糕時,會加入發粉。
1. 發粉在製造麵包和蛋糕時有何用處?
2.利用化學方程式,解釋發粉的作用。

2007-04-10 12:38:23 · 1 個解答 · 發問者家浩 1 in 化學

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冷氣為何有抽濕作用??

2007-04-10 12:14:44 · 1 個解答 · 發問者聶風 2 in 化學

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for each of the folowing pairs of substances, suggest a simple chemical test to distinguish one substance from the other and state the expected observation( Flame test is not accepted)

a zinc nitrate and magnesium nitrate

- 如果我加入NaOH- into zinc nitrate and magnesium nitrate, 2者就會有white ppt. 啦~
咁如果再加入excess NaOH- zinc nitrate 係唔係會變成colourless?
咁如果再加入 excess NaOH- magnesium nitrate 係唔係都係white ppt.?

2007-04-10 09:53:17 · 1 個解答 · 發問者 ? 1 in 化學

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f.4 chemistry

on complete combustion, a 3.41 g of compound (CxHyOz) produced 8.6 g of carbon dioxide and 1.51 g of water.WHAT IS The empirical formula of the compound .

HOW TO DO??????

2007-04-10 09:37:24 · 2 個解答 · 發問者 carolene 1 in 化學

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enthalpy change...please help

please help

Consider the reaction:
ICl(s)I(g) +Cl(g) △H= +210kJmol-1
Explain why this value of △H is not the same as that of the I---Cl bond enthalpy.

20 marks will be given to the best solution

2007-04-10 08:21:28 · 1 個解答 · 發問者 Wilson 2 in 化學

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enthalpy change...please help

please help....

1.Consider the reaction:
Ch4(g)+Cl2(g)  CH3Cl(g) +HCl(g)
a.
what bonds are broken and what bonds are formed?
b.
Calculate:
i. the energy required to break these bonds
ii. the energy released on forming the bonds
E(C---H)=415kJmol-1; E(Cl---Cl) = 242 kJmol-1; E(C---Cl) = 338 kJmol-1;
E(H---Cl)=431kJmol-1

2007-04-10 08:19:59 · 1 個解答 · 發問者 Wilson 2 in 化學

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standard enthalpy change of formation

Please help me to solve these questions

Using the values of standard enthalpy change of formation given calculate the values of△H for the following reactions:

a. the thermal decomposition of BaCO3
b. C2H6(g) +Br2(l)  C2H5Br(l)+ HBr(g)
c. C2H4(g) + H2O(l) C2H5OH(l)
d. TiCl4(l) +2Mg(s)  Ti(s)+2MgCl2(s)
e. SO3(l) + H2O(l) H2SO4(l)

Thanks!!
20 marks will be given to the best solution!!! Thanks very much!!!

2007-04-10 08:05:56 · 1 個解答 · 發問者 Wilson 2 in 化學

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Chem-chemical eqaution(precipitate)

1) 2AgNO3(aq) + CaCl2(aq) ---> 2AgCl (s) + Ca(NO3)2 (aq)

2) Na2CO3(aq) + CuSO4(aq) ---> CuCO3 (s) + Na2SO4(aq)

題目問2隻solution mix埋之後邊pair會give a precipitate
咁以上2條equation都係correct ,有 precipitate

寫equation個陣...
2種solution mix埋之後點分辨佢ge product 邊隻係solid邊隻係aq ???

2007-04-10 06:44:46 · 1 個解答 · 發問者 ? 3 in 化學

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E=MC 2 is?

E=MC 2 is?

please answer me!!!!!!!!!!!!!!!!!!!!!!!

2007-04-10 06:37:43 · 2 個解答 · 發問者 Ram2007 3 in 化學

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請問氧化鋁陶瓷的用途跟發展??

請問氧化鋁陶瓷用在什麼產業跟設備中功能又為何呢??
未來的發展性又能到什麼樣的地步呢?傳統行業跟科技行業都用的到嗎? 煩請解答感謝萬分

2007-04-10 06:23:08 · 1 個解答 · 發問者 nancynonno 1 in 化學

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EGC.EC.EGCG...的曲線圖解說..有點不懂

FIGURE 4. Trolox equivalent (TE) values of pooled plasma to which
different concentrations of ()-epigallocatechin (EGC), ()-epicatechin
(EC), ()-epigallocatechin-3-gallate (EGCG), ()-epicatechin-3-gallate
(ECG), or a mixture of the 4 flavanols were added (A) or to which the same
concentrations of the flavanols were added (B). Values are the mean (<+->SEM)
of 3 determinations per time point. Antioxidant activity was determined by
using the trolox equivalent antioxidant capacity assay, which measured the
reduction in the radical cation 2,2'-azinobis-(3-ethylbenzothiazoline-6-
sulfonic acid) diammonium salt.

2007-04-09 21:53:04 · 1 個解答 · 發問者 Stanley 1 in 化學

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有關綠茶紅茶曲線圖解說...有點不懂

FIGURE 2. Mean (<+->SEM) plasma total flavanol concentrations [sum of
plasma ()-epigallocatechin, ()-epicatechin, ()-epigallocatechin-3-
gallate, and ()-epicatechin-3-gallate concentrations] after the consumption
of green tea, black tea, or a green tea extract supplement by 28–30 healthy
subjects.

TABLE 3
Percentage of the total dose of ingested ()-epigallocatechin (EGC), ()-epicatechin (EC), ()-epigallocatechin-3-gallate (EGCG), and ()-epicatechin-
3-gallate (ECG) from green tea (GT), black tea (BT), and a green tea extract supplement (GTS) in plasma and urine1

1 All values are x<+->SEM; n = 28–30 participants in a randomized crossover design. Means in a row with different superscript letters are significantly
different, P < 0.05 (mixed-model ANOVA and Tukey’s method).

2007-04-09 21:46:47 · 1 個解答 · 發問者 Stanley 1 in 化學

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有關綠茶紅茶,黃烷醇劑量管理的表格敘述可以幫我解說下咩

Flavanol content of green tea (GT), black tea (BT), and a green tea extract supplement (GTS) administered as a one-time dose1

1 All values are the x<+-> SD of 2 measurements. EGC, (-)-epigallocatechin; EC, (-)-epicatechin; EGCG, (-)-epigallocatechin gallate; ECG, (-)-
epicatechin gallate. The flavanol content was analyzed by using HPLC with a binary gradient and ultraviolet visible detection. Means in a row with different
superscript letters are significantly different, P <0.05 (mixed-model ANOVA and Tukey’s method).

2007-04-09 21:38:52 · 1 個解答 · 發問者 Stanley 1 in 化學

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some chem questions!!!!!!!!!!!!!!

1.點解sodium carbonate會係alkaline?
佢同acid反應唔係會有carbon dioxide出現架咩?

2.點先叫efferressence occurs?why有hydrogen only叫gas bubble
有carbon dioxide叫efferressence occurs?

3.calcium hydroxide係slightly soluble in water,咁叫係alkaline呀?

4.點解chem書成日都話pipette係25cm^3?

5.點解呢dilute acid，即係加左水係d acid到，點解the no.of mole of the solute會一樣呀?
點解唔會多左呢?因為多左水既molecules呀嘛?why??

2007-04-09 17:58:00 · 1 個解答 · 發問者 doremi 1 in 化學

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哪些是強力磁鐵?

問各位高人強力磁鐵有哪幾種(請由最強的開始排) 書局訂ㄉ到ㄇ

2007-04-09 16:15:13 · 1 個解答 · 發問者 Julie 1 in 其他：科學

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電磁波為什麼可以加熱?鐵為什麼不行?

如同上面所說的　大大們　為什麼可以加熱　那鐵為什麼不行

難到放鐵就會爆炸＠＠？

我要寫功課用　最好的話是　６００個字以上　拜託＞＜

幫我解答＝　＝

2007-04-09 14:55:25 · 1 個解答 · 發問者 Anonymous in 其他：科學

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丙-1-醇的燃燒熱

丙-1-醇的燃燒熱多少?

2007-04-09 14:51:49 · 1 個解答 · 發問者 ? 1 in 化學

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ce化學!!!!!!!!!!!

氯離子和氫離子之間是離子鍵
氯化氫氣體理應是離子化合物先係??
點解氯化氫氣體係共價化合物

2007-04-09 14:30:11 · 2 個解答 · 發問者 ? 2 in 化學

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物理實驗作用力跟反作用力

http://tw.knowledge.yahoo.com/question/?qid=1306012711169

我在這篇文章中看見以下這個實驗

1)瓶子火箭，材料：空瓶子.軟木塞.杯子.小蘇打(碳酸氫鈉)粉.醋.衛生紙.圓形木棒或鉛筆
步驟
[1]在瓶子中加入比例為1：1的醋和水
[2]剪下小張的衛生紙把小蘇打粉包起來
[3]把包起來的小蘇打份放置於瓶子當中(瓶中已有液體)
[4]把軟木塞塞在瓶口放再排在平行的鉛筆或圓體木棒上(減少與地面的摩差力)
[5]等待裡面的衛生紙被溶液穿透之後，醋酸將與衛生紙裡面的小蘇打反應產生ＣＯ2.等到裡面壓力增大塞子承受不住時.氣體會把塞子往後彈出瓶子將會往前推進!!

此實驗的原理：作用力與反作用力

我想請問，有人可以告訴我這實驗更詳細的作用力和反作用力運動的情況嗎?!

2007-04-09 14:12:21 · 2 個解答 · 發問者波蜜 2 in 其他：科學

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點解第1族元素既熔點會從上而下遞減??

第1族元素原子數目會從上而下遞增,咁即係話金屬鍵應該會越來越強,但點解熔點反而會遞減呢????

2007-04-09 14:05:44 · 1 個解答 · 發問者 STEVIE-G™ 7 in 化學

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聚酯係咪熱固性塑膠?

2007-04-09 13:59:11 · 1 個解答 · 發問者 STEVIE-G™ 7 in 化學

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enthalpy change...can anyone help me?

this is the questions
100 cm cube of water were placed in a plastic beaker The temperature was 18.7 C. 16.6 g of solid potassium iodide were added and the temperature fell to 13.4 C.
(take the c of water be 4.18 J/g/C)

a.
In this experiment it is necessary to make the potassium iodide dissolve as quickly as possible. Explain why. How is this brought about?

2007-04-09 12:19:04 · 1 個解答 · 發問者 Wilson 2 in 化學