穎新 發問於 科學及數學化學 · 6 年前

Chemistry 溫習題目 2

The following table gives some information on three metals P, Q and R and their oxides.

Metal / P / Q / R

Method of storage / Under paraffin oil / In an air-tight container / In a safe container

Colour of metal oxide / White / White / Red

a) Oxides of P and Q give a golden yellow and a brick-red flame in the flame test respectively.

(i) Describe the steps of carrying out the flame test.

(ii) Suggest what P and Q might be.

b) Explain why P has to be stored under paraffin oil.

c) (i) Describe the observations when P is added to cold water.

(ii) Is the resultant solution acidic or alkaline? What is the colour change of the red litmus paper if it is dipped into the solution?

d) A colourless gas forms when Q is added to dilute hydrochloric acid.

(i) Draw a labelled diagram to show how the gas can be collected.

(ii) Suggest a test for the gas and state the positive result.

e) R reacts with oxygen on very strong heating.

(i) Suggest what R might be.

(ii) State ONE use of R.

f) Arrange P, Q, and R in decreasing order of reactivity.

g) Suggest the methods of extraction for P, Q, and R from their metal oxides.

完全唔識,請幫幫手~~~

1 個解答

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  • 6 年前
    最愛解答

    a)

    (i)(這個要背出來啊...)

    1) Moisten a clean platinum/nichrome wire with concentrated hydrochloric acid.

    2) Dip the wire into a crushed sample.

    3) Heat the end of the wire strongly with a non-luminous flame.

    (ii)

    P: sodium

    Q: Calcium

    b) P reacts with air readily.

    c)

    (i)

    1) P melts to form a silvery ball.

    2) It moves quickly on the water surface with a hissing sound.

    3) It burns with a golden yellow flame.

    (ii)

    The resultant solution is alkaline. Red litmus paper turns from red to blue.

    d)

    (i) http://i.imgur.com/6kVUkw0.jpg

    (ii) Test the gas with a burning splint. Hydrogen gas burns with a pop sound.

    e)

    (i) Mercury

    (ii) Make thermometers.

    f) P, Q, R

    g)

    P: electrolysis of molten metal oxide

    Q: electrolysis of molten metal oxide

    R: direct heating

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