1.2007/Q7a
This question involves how to distinguish four labelled test tubes, each containing one of the following colourless liquids: methanol, concentrated sodium hydroxide solution, distilled water, hexane.
a. By heating a small amount of each of the colourless liquids to dryness, one of the liquids can be distinguished. Suggest which liquid can be distinquished, and state the observation involved.
2.2004/Q1
Calcium reacts with cold water to give a colourless gas.
a. The sudent recorded the following observation in his laboratory report: 'Evolution of the colourless gas was at first slow but became faster after some time.'. Suggest an explanation for the student's observation.
3.Teflon is a plastic that can be used to make artificial hip joints. Teflon is an addition polymer of linear structure consisting of carbon and fluoringe only. THe ration of the number of carbon atoms to the number of the fluoring atoms in the polymer is 1:2.
a. Draw a portion of the teflon structure with 10 carbon atoms.
b. Write the repeating unit of teflon, and suggest a possible monomer of teflon.
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F.4 Chem功課....係會考題目(20點)
2011-08-16 4:18 am
回答 (3)
2011-08-16 7:49 am
✔ 最佳答案
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參考: miraco
2011-08-16 7:02 am
* When the calcium is add in to the cold water, the calcium will be sink ,so there is no colourless gas but colourless gas bubbles will evolved.
Question2.2004/Q1
Calcium reacts with cold water to give a colourless gas.
a. The sudent recorded the following observation in his laboratory report: 'Evolution of the colourless gas was at first slow but became faster after some time.'. Suggest an explanation for the student's observation.
Answer
When the calcium is added in to cold water, a layer of calcium hydroxide will formed at first when react with cold water, after that the calcium hydroxide will fall off, so the calcium can continuously react with the cold water, so the evolution of the colourless gas was at first slow but became faster after some time.
Question2.2004/Q1
Calcium reacts with cold water to give a colourless gas.
a. The sudent recorded the following observation in his laboratory report: 'Evolution of the colourless gas was at first slow but became faster after some time.'. Suggest an explanation for the student's observation.
Answer
When the calcium is added in to cold water, a layer of calcium hydroxide will formed at first when react with cold water, after that the calcium hydroxide will fall off, so the calcium can continuously react with the cold water, so the evolution of the colourless gas was at first slow but became faster after some time.
參考: myself
收錄日期: 2021-05-01 10:03:49
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