1)'Filtration process cannot be used to get pure water from sea water'
State the underlying principle of filtration and explain the above statement.
2)Both oxygen and element X(nitrogen?)can be obtained by the fractional distillation of liquid air.
(i)Where does the fractional distillation of liquid air take place in industry?
(ii)Explain briefly why oxygen and element X can be obtained by the fractional distillation of liquid air.
(iii)Suggest a chemical test which allows you to distinguish between oxygen and element X.
3)State the procedures in the two experiments showing the presence of sodium ions?
4)Explain why the concentration of carbon dioxide in the atmosphere has been increased largely in the past 50 years.
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Chem問題(F.3)
2013-07-22 9:44 pm
回答 (2)
2013-07-22 11:05 pm
✔ 最佳答案
1.Filtration is used to separate insoluble substances form a mixture,since the chemicals in sea water are dissolved in it, they cannot be separate by filtration and pure water cannot be obtained.2i. air separation plant
ii. it's because their boiling points are different, when the temperature reaches the lower boiling point, one of the gases will vaporize and escape form the liquid mixture of the two gases,hence they can be obtained respectively.
iii glowing splint test,oxygen can relight the glowing splint buy gas X must not.
3. --flame test
step 1 moist and clean the platinum wire in concentrated hydrochloric acid
step 2 dip the wire in the crashed sample being tested
step 3 burn the wire in non-luminous flame and observe the flame color(sodium係golden-yellow)
4.because of the increased usage of motor vehicles which emit CO2 as one of the exhaust gases , the CO2 concentration in the atmosphere has been increased largely.
2013-07-22 11:08 pm
NOTE: According to http://www2.volstate.edu/chem/1120/Qual_Anal_I.html ,
Flame test is probably the only way to test for sodium ions since the sodium ion is always soluble in water
Flame test is probably the only way to test for sodium ions since the sodium ion is always soluble in water
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