问几个sample questions上的题

zhutoushyUID: 2217884

9. For aqueous solution, Raman measurements are usually preferable to the corresponding infrared measurements because
A. scattering problems due to tiny amounts of suspended impurities in the sample are much more severe i n the infrared
B. Raman measurements are more sensitive and permit much smaller concentrations to be determined
C. Raman measurements are easilu capable of much greater resolution than infrared because shorter wavelengths are used
D. few water-soluble substances absorb in the infrared
E. water has absorption bands in the 2-15 micron region an d comparatively small portions of the spectrum are left free for measurements of solutes

21.弱酸溶液中是不是只能用强酸型离子交换树脂？

118. A detailed study of the infrared spectrum of a diatomic molecule can leda directly to all of  the following pieces of information EXCEPT the
A. translational energy of the molecule
B. force constant of the bond
C. relative distribution of molecules among the allowed rotaional levels
D. average bond distance
E. relative isotopic abundance

135. For a molecules, the thermal energy predicted by quantum theory agrees best with the energy predicted by classical theory for those cases in which the
A. allowed energy levels are closely spaced compared to kT
B. allowed energy levels are widely spaced compared to kT
C. system is at very low temperature
D. total energy is contributed mostly by vibrational motion
E. model used is a particle confined to a box approximately 1 cubic angstrom or less in volume

希望好心人解答,谢谢了!

seolforUID: 2238537

9
拉曼可以测量水溶液而红外不行，红外光会被水吸收，而拉曼不会

21
弱酸应该用强阴离子交换树脂可能好点吧，这个我也不太清楚，大家讨论讨论

118
平动能不能够通过红外测量，红外只能测转动和振动能级差。

135
能级差远小于KT时，根据玻尔兹曼分布，exp[-(Ea-Eb)/KT]就趋近于一，也就是说量子化效应可以忽略，这时体系过渡到经典体系。也就是说可以用经典力学的方法处理。

zhutoushyUID: 2217884

恩，学习了，谢谢！