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Suk Ka asked in 科學及數學化學 · 1 decade ago

f.4 chemistry

25 Selenium Se is a group VI element of the periodic table. Which of the following statements concerning selenium are correct?

1 Selenium forms a covalent hydride

2 The chloride of selenium is a solid with network structure

3 Selenium forms Se2- ion when reacted with Group I elements

A 1 2

B 1 3

C 2 3

D 1 2 3

26 Which of the following metals is used I making jewellery?

A Gold

B Tin

C Aluminium

D Lead

27 Which of the following statements concerning aluminium is/are correct?

1 Aluminium was used earlier than iron in the history of mankind

2 Aluminium is more abundant than iron in the Earth’s crust

3 Aluminium can be extracted by electrolysis

A 1

B 2

C 1 3

D 2 3

28 Which of the following statements is correct?

A Aluminium is the only metal that is recycled to a large extent

B The resources of iron will last for about 1000 years

C Recycling helps reduse the waste disposal problems

D It is economical to recycle metals because the cost of extration is higher than the cost of recycling

29 Which of the following metals burns with a brick-red flame?

A K

B Na

C Ca

D Mg

30 Which of the following metals are shiny when freshly cut but rapidly tarnishes in air?

1 K

2 Na

3 Zn

A 1 2

B 1 3

C 2 3

D 1 2 3

31 In which of the following experiments would hydrogen be produced?

1 Electrolysis of sea water

2 Passing steam over Mg

3 Adding Fe to dilute hydrochloric acid

A 1 2

B 1 3

C 2 3

D 1 2 3

32 When sodium hypochlorite solution is exposed to sunlight, it decomposes according to the following equation:

xNaOCl(aq)-> yNaCl(aq) + zO2(g)

Which of the following combinations is correct?

X y z

A 2 1 1

B 2 2 1

C 1 2 1

D 2 1 2

33 Which of the following will NOT react with each other?

A Zn and steam

B Fe and dilute sulphuric acid

C Ag and Copper(II) sulphuric solution

D Lead and oxygen

1 Answer

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  • 1 decade ago
    Favorite Answer

    25

    1正確,硒和氫都是非金屬,可以形成共價氫化物

    2不正確,氯化硒具簡單分子結構,不具巨型網狀結構

    3正確,它和第一族會形成離子化合物,形成Se2-離子

    所以答案是B 1,3

    26

    A正確 金具光澤,質輕,外觀令

    B,C,D不正確錫,鋁,鉛都帶灰暗色,不合用

    27

    1不正確,鋁的活潑性高於鐵,較難提取

    2正確,鋁在地中的含量排第三,第一是氧,第二是硅

    3正確,鋁的提取方法是電解

    所以答案是D 2,3

    28

    答案是C 回收當然有助减少廢物棄置

    A不正確,其他金屬也會回收

    D不正確,回收成本很貴的

    29 答案是C 鈣有磚紅色的火焰

    A鉀是紫色火焰

    B鈉是金黃色火焰

    D鎂沒有特別色的火焰

    30

    1正確,鉀是第一族,非常活潑可cut

    2正確,鈉是第一族,非常活潑可cut

    3不正確,鋅是過渡金屬,不太活潑,不可cut

    答案是A 1,2

    31

    1是正確 電解陽極得氯氣,陰極得氫氣

    2是正確 鎂和水蒸氣反應得出氫氣 方程如下

     Mg(s)+H2O(g)生成MgO(s)+H2(g)

    3正確,鐵和氫氯酸反應得出氫氣 方程如下

     Fe(s)+2HCl(aq)生成FeCl2(aq)+H2(g)

    所以答案是D 1,2,3

    32

    2NaOCl(aq)生成2NaCl(aq)+O2(g)

    所以答案是B 221

    33

    A不正確,鋅和水蒸氣有反應

    Zn+H2O生成ZnO+H2

    B不正確,鐵和硫酸會反應

    Fe+H2SO4生成FeSO4+H2

    C正確 銀的活潑性低於銅,不可以發生置換反應

    D不正確 鉛和氧氣有反應

    2Pb+O2生成2PbO

    所以答案是C

    2010-02-07 19:24:29 補充:

    可cut是指容易切割

    2010-02-07 19:26:45 補充:

    tarnishes代表失去光澤

    由於鉀同鈉非常活潑,容易和空氣反應

    4K+O2生成2K2O

    4Na+O2生成2Na2O

    K和Na是有光澤的

    K2O和Na2O是灰暗色的,代表失去光澤

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