中四化學問題 titration

[匿名]

2011-03-24 7:10 am

Both dilute sodium hydroxide solution and dilute ammonia solution should be standardized before used for titration. Explain.

Sodium hydroxide (aq):

Ammonia (aq) :

不過其實知唔知個molarity又有冇所謂呢，反正都係加到d indicator 變色ge 姐？

回答 (2)

知識就是力量

2011-03-25 5:04 am

✔ 最佳答案

They both should be standardized to minimize error to affect the molarity of moles of NaOH and NH3 in pipette.

This is because water is used to rinse the pipette, remaining water droplets would increase the volume of the bases and hence molarity of them, if the number of moles of NaOH and NH3 are kept in constant.

2011-03-24 21:05:42 補充：
Correction:
They both should be standardized to minimize error to affect the molarity of NaOH and NH3 in pipette.

2011-03-24 21:11:09 補充：
Since the molarity of them is changed, the volume of solution, that use to be titrated reacting with these solutions are also changed, experimental error occurs.

參考: Knowledge is power.

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明仔

2011-03-24 7:15 am

可唔可以詳細D講嘢呀????

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