F4 chem question(40marks)高手in 要有explain

2007-10-11 8:18 am

1which of the following substance,when mixed undergo a chemical equation?
A Iron and calcium nitrate solution
BCopper and water
CLead and Steam
DZinc and Lead(II) nitrate solution
2.X,Y,Z are metals.At high tempreature,carbon will remove oxygen from the oxides of Z and Y but not from that of X,Z displace Y from solution of the nitrate of Y.Which following represents the ascending order of reativity of three element?

回答 (1)

Jacob

2007-10-11 8:37 am

✔ 最佳答案

1) 唔記得個名叫咩只係記得有個排序係講個元素鍾意變成ion的趨勢
K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au

A : 就算有reaction都只係displacement不過根據上面個排序 Fe 後過 Ca 所以冇反應

B : 常識。你幾可見一舊有光澤的銅同水有反應?

C : 金屬同水(liquid/gas)有反應只係去到Fe，所以冇反應

D : 睇上面排位 Zn 高過Pb 所以會有displacement出現有反應產生
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2) 用碳去還原金屬氧化物只限於該金屬的活潑性不高
所以就以上情況 x 有最高的reactivity

而y及z中作比較 z可從y+溶液中displace y出黎表示 z的活潑性較y高

所以x>z>y

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