點解在實驗室做cracking要在porcelain上加熱?
回應番一條問題:
During cracking in laboratory, the cotton wool (soaked with medicinal paraffin) should not not be heated directly because
A) this will char the cotton wool.
B) the paraffin will burn.
C) the paraffin will escape as vapour without reaction.
D) the paraffin will react with cotton wool at high temperature.
點解在實驗室做cracking要在porcelain上加熱?
2009-03-01 11:59 pm
回答 (1)
2009-03-02 1:01 am
✔ 最佳答案
The answer is C.Whether the cotton wool chars or not does not affect the cracking. So, A is false.
The amount of air in the tube is too low to burn the paraffin. So, B is false.
If the paraffin escapes in a very fast rate, it will pass quickly over the procelain which is not sufficiently hot. Therefore, most paraffin vapour will not react. So, C is true.
Paraffin would not reat with cotton wool even at high temperature. So, D is false.
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