w_nmr_all - Exam Name_ SHORT ANSWER. Write the word or...

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Exam Name___________________________________ SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 1) Calculate the magnetic field that corresponds to the proton resonance frequency of 300.00 MHz. The gyromagnetic ratio of the 1 H nucleus is 26,753 s - 1 gauss - 1 . 1) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question 2) A nucleus with an __________ atomic number or an __________ mass number has a nuclear spin that can be observed by the NMR spectrometer. A) even, odd B) odd, even C) even, even D) odd, odd 2) SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 3) What three - word term is abbreviated NMR? 3) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question 4) How many nuclear spin states are allowed for the 1 H nucleus? A) 1 B) 4 C) 2 D) 3 E) 10 4) 5) The energy difference between the allowed spin states for an 1 H nucleus is __________ the strength of the external magnetic field in which it is placed. A) exponentially related to B) directly proportional to C) inversely proportional to D) logarithmically related to E) independent of 5) 6) 1 H nuclei located near electronegative atoms tend to be __________ relative to 1 H nuclei which are not. A) split B) deshielded C) resonanced D) shielded E) none of the above 6) 7) Electromagnetic radiation in the __________ region is used in 1 H NMR spectroscopy. A) X - ray B) ultraviolet C) microwave D) infrared E) radio wave 7) SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 8) __________ is commonly used as an internal reference in NMR spectroscopy; its signal is assigned d = 0 in 1 H and 13 C NMR spectroscopy. 8) 1
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9) On a 90 MHz spectrometer, calculate the frequency at which a proton absorbs if it appears at 4.20 ppm. 9) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question 10) Using a 60 - MHz spectrometer, the protons in dichloromethane appear at 5.30 ppm. When the same sample is placed in a 100 - MHz instrument, where does the signal appear? A) 3.18 B) 8.33 C) 5.30 D) cannot be determined from information given 10) 11) The protons marked H a and H b in the molecule below are __________. A) diastereotopic B) chemically equivalent C) enantiotopic D) endotopic E) none of the above 11) 12) The protons marked H a and H b in the molecule below are __________. A) enantiotopic B) diastereotopic C) chemically equivalent D) endotopic E) none of the above 12) 13) The protons marked H a and H b in the molecule below are __________. A) endotopic B) chemically equivalent C) enantiotopic D) diastereotopic E) none of the above 13) ESSAY. Write your answer in the space provided or on a separate sheet of paper. 14) The chair form of cyclohexane has protons in two distinct environments, axial and equatorial. When the proton NMR of cyclohexane is run on a 100 - MHz instrument at 23°C, only one signal for the compound is observed.
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This note was uploaded on 12/17/2010 for the course CHEM 101 taught by Professor Silva during the Spring '08 term at Binghamton University.

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w_nmr_all - Exam Name_ SHORT ANSWER. Write the word or...

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