Question

(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

(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

(3 pts) The absorbances present 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

(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

(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

Answer 1

c) The absorbances present in an IR spectrum result from - chemical bond deformations such as bends and stretches

d) In the proton NMR spectrum the peak at 0 ppm is due to TMS (Tetra methyl silane)

f) For a proton that has six nearest neighboring protons, what signal splitting (i.e. how many peaks) would we observe in the proton NMR?

septet (7) because of n+1 rule

g) A compound with an empirical formula C3H8O has a D. U. of - " 0 "

h) What functional group could be present in a compound with a molecular formula C3H8O?

  C-OH