1. The hazard warning label flammable is found on a reagent bottle. Which of the following gases may be contained in the reagent bottle?
A. hydrogen B. oxygen C. chlorine D. argon
2. Which of the following correctly describes the sequence of procedures to separate sand, salt and water from a mixture of sand and salt solution?
A. filtration and evaporation B. filtration and distillation
C. crystallisation and filtration D. crystallisation, filtration and distillation
5. Which of the following has physical change? Which of the following have chemical change?
A. mixing sea water with silver nitrate solution
B. evaporation of sea water
C. electrolysis of sea water
f.3 chem
2012-01-08 12:28 pm
回答 (2)
2012-01-09 7:50 am
1. A (oxygen supports burning but it is not flammable, hydrogen gives out a "pop" sound in the presence of burning splint, the pop sound is in fact a small explosion, which indicates hydrogen is flammable)
2. B (Firstly, separate the insoluble substances, i.e. sand, from the mixture by filtration. Then, distillate the filtrate by disillation.)
3.Physical Change: B (No new substance is formed)
Chemical Change: A(New substance,white precipitate(silver chloride) is formed ) and C (New substances, hydrogen gas, chlorine gas, sodium hydroxide solution, is formed)
Give me the points plz! :)
2. B (Firstly, separate the insoluble substances, i.e. sand, from the mixture by filtration. Then, distillate the filtrate by disillation.)
3.Physical Change: B (No new substance is formed)
Chemical Change: A(New substance,white precipitate(silver chloride) is formed ) and C (New substances, hydrogen gas, chlorine gas, sodium hydroxide solution, is formed)
Give me the points plz! :)
參考: myself(I am a S3 student too)
2012-01-08 7:26 pm
1. A (hydrogen is highly flammable)
2. B (someone will choose A, but evaporation cannot collect water)
5. physical change : B, Chemical change : A,C
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2. B (someone will choose A, but evaporation cannot collect water)
5. physical change : B, Chemical change : A,C
如有不足/有錯
請發信聯絡
另外，嚴禁抄襲！
請發問者/投票者慎選答案
還有的是人家答了大家就不要答！
加我好友^_^
參考: 大學 Minor Chemistry
收錄日期: 2021-05-03 03:00:49
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