1. (40 points) Select the best answer from the choices provided. a. (3 pts) In the mass spectrum on page 3 what name do we give the peak at 150 m/z units? (1) base peak (2) molecular ion (3) molecular fragment (4) baseline b. (3 pts) In the mass spectrum on page 3 what name do we give the peak at 135 m/z units? (1) base peak (2) molecular ion (3) molecular fragment (4) baseline c. (3 pts) The absorbancespresent in an IR spectrum result from: (1) “spin flipping” of nuclei (2) fragmentation of the molecule (3) chemical bond deformations such as bends and stretches d. (3 pts) In the proton NMR spectrum on page 3 what is the peak at 0 ppm? (1) a peak associated with the molecule (2) TMS e. (3 pts) What causes chemical shift differences for nuclei in the NMR spectrum? (1) different electronic environments (2) similar electronic environments (3) interaction between molecules (4) molecular movement in solution f. (3 pts) For a proton that has six nearest neighboring protons what signal splitting (i.e. how many peaks) would we observe in the proton NMR? (1) quintet (5) (2) septet (7) (3) sextet (6) (4) quartet (4) g. (4 pts) A compound with an empirical formula C3H8O has a D. U. of: (1) 1 (2) 0 (3) 3 (4) ½ h. (3 pts) What functional group could be present in a compound with a molecular formula C3H8O? (1) C-OH (2) C=O (3) COOH (4) COOR i. (15 pts) Consider the following molecule and answer the questions below: (1) How many different types of carbons are present in this molecule? (2) On the structure above indicate each different carbon type by circling them and numbering them. (3) How many different types of protons are present in this molecule? (4) How many degrees of unsaturation are present in this molecule? (5) Where would the benzene ring C=C stretching frequencies be found in the IR spectrum of this compound? 2. (60 points) Use Mass; Infrared;1H and 13C NMR spectra to solve the structure for the molecule withthe following elemental composition: Carbon – 71.98%; H – 6.71%; O – 21.31%. Show all work in the space below to justify the structure you draw. You may do your combustion analysis calculations on a separate sheet and attach to the quiz. EF = MF = DU = Mass Spec: IR: 1H NMR: 13C Spectral Data: Draw Structure In the box above Quartet 27.0 ppm Doublet 129.6 ppm Singlet 196.5 ppm Quartet 56.0 ppm Singlet 129.7 ppm Doublet 114.0 ppm Singlet 166.4 ppm
