《有机化合物熔点和沸点的测定（determination of melting point and boiling point of organic compounds）》由会员分享，可在线阅读，更多相关《有机化合物熔点和沸点的测定（determination of melting point and boiling point of organic compounds）（9页珍藏版）》请在金锄头文库上搜索。
1、有机化合物熔点和沸点的测定（Determination of melting point and boiling point of organic compounds）Question 1: what happens if the capillary is not sealed?Question 2: why should a clean surface dish be used?Question 3: if the sample in the sample tube is not compacted, what is the effect on the result?Question 4:
2、why can use liquid paraffin as the bath?Question 5: where should a rubber band be located? Why?Question 6: how to control the flame temperature?Question 7: when approaching the melting point, why should the heating rate be controlled very slowly? Such as warming too fast, what is the impact?Question
3、 8: is it possible to use second organic compounds that have been fused for the first time after measuring the melting point? Why?Question 9: if the sample to be obtained is too small or too small, what is the effect on the measurement result?Thinking question answer:Thinking 1 answer: there will be
4、 liquid paraffin into the capillary, affect the observation of solid melting.Question 2 answer: prevent impurities mixed into the capillary so that the melting point is not accurate.Question 3 answer: the melting of solid matter is not complete, affecting the observation of the melting process and m
5、elting point judgment.Thinking 4 answer: liquid paraffin boiling point higher.Question 5: a rubber ring to the top in the bath. If it is below the liquid level, the rubber band expands as the temperature increases,The capillary will fall off and cause the experiment to fail.Question 6 answer: alcoho
6、l lamp from time to time, suspended heating.Think 7 answer: if the temperature is too fast, it will cause the material to melt rapidly and can not observe the melting point distance.Think 8 questions: No, this is because the first time after the melting point, sometimes some substances will produce
7、partial decomposition, some willChange into other crystalline forms with different melting points.Thinking 9 answer: if the sample to be taken too much, the internal pressure of the larger liquid, will make the last bubble out, can not really reflect the boiling point temperature. If the sample is t
8、oo small, it is possible that the boiling point has not been detected and that the liquid has evaporated.Test point 1. the melting point of a compound is (?).A. at atmospheric pressure, the temperature at which the solid-liquid phase reaches equilibrium is B. when the solid-liquid phase reaches equi
9、librium at any atmospheric pressuretemperatureTest questions 2. The method of determining melting point is ().A. capillary method, B. melting point method, C. distillation method, D. fractionation methodTest questions 3. when measuring the melting point, the position of the flame heating.A.b shape p
10、ipe bottom B.b shape tube, two branch pipe intersection, C.b shape pipe, upper branch pipe mouth D. any positionTest questions 4. when measuring the melting point, the position of the mercury bulb in the thermometer.A.b shape pipe bottom, B.b tube, two branch pipe, C. liquid level in the middle of a
11、ny positionTest questions 5. measuring the melting point, the rubber ring position ().A. C. position on the B. level below the liquid levelTest questions 6. trace method of boiling point, thermometer, mercury ball position ().A.b shape pipe bottom, B.b tube, two branch pipe, C. liquid level in the m
12、iddle of any positionTest 7. Trace the position of the rubber ring in the boiling point.A. C. position on the B. level below the liquid levelTest questions 8. trace method of boiling point, melting point tube how to place ().A. do not seal, put directly into the inner pipe, B. seal, closed end down
13、into the inner tubeC. sealing, closed end, upward, into the inner tubeTest questions 9., the boiling point should be recorded, the boiling point temperature should be recorded.A. the temperature at which the first bubble appears in the inner tube of the B. and the temperature of the continuous bubbl
14、e in the inner tubeThe temperature at which the last bubble in the inner tube of the C. is no longer emitted and retractedTest title 10. when adding nonvolatile solutes to a volatile liquid ()A. has no effect on boiling point; boiling point of B. decreases; boiling point of C. increases.Test questio
15、ns 11. What is wrong in the following statement is.A, melting point means the temperature in which the solid and liquid coexistThe melting range of B and pure compounds is generally between 0.5 and 1 degrees centigradeC and melting point are the convenient and effective methods to determine the purity of solid compoundsD, the initial melting temperature means the temperature at which the solid substance softensTest questions 12.What is correct in the following statement is.A and impurities increase the melting point and lengthen the melting distanceB, the oil bath with par
