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小匿 發問於 科學及數學化學 · 1 十年前


1)for each of the followingtasks,name the method that should be used to accomplish the task.

A)to separate a mixture of sand and water.

B)to obtain common salt from sea water.

C)to obtain pure water from sea water.

2)suggest chemical test for each of the following substances and state the expected observations in each test.


B)solid sodium chloride

3)the________is a gaseous layer surrounding the earth.

2 個解答

  • ?
    Lv 7
    1 十年前


    A) filtration

    B) evaporation

    C) distillation


    A) Water turns anhydrous cobalt(II) chloride paper from blue to pink. (Alternatively : Water turns anhydrous copper(II) sulphate from white to blue.)

    B) Show that it is a sodium compound by giving a bright yellow flame in flame test. Show that it is a chloride compound by forming a white ppt when mixing the solution of the compound with acidified silver nitrate solution.



  • 1 十年前

    1 A) Sedimentation B) Evaporation C) Reverse Osmosis

    2 A) Turn anhydrous cobalt chloride from blue to red. B) Disssolve the salt in water, carry out flame test, Na+ produce golden yellow flame. Add the salt to conc H2SO4 will produce yellow Cl2 which can bleach pH paper.

    3) Ozone