Question

Lab 6 Mass Spectrometry Worksheet Please show your work for the following problems in your laboratory notebook. Your notebook carbons will be collected at the beginning of the next lab period. 1. For each of the following molecular formulas, calculate the index of hydrogen deficiency (IHD), and draw at least two possible structures: a. CaH4 22+2--6+04-2 b. CaHs c. CoHsNO2 26)-54t 4 d. CHioBr2 2 215)+2--0+o 2. Write the molecular formulas for three hydrocarbons with the following molecular ion (M) peak values, and calculate the IHD for each: a. M' peak m/z- 86 b. M' peak m/z110 c. M' peak m/z = 190 3. Determine two molecular formulas for compounds (not limited to hydrocarbons) that have the following molecular ion peak values in their mass spectra. Calculate the IHD for each molecular formula you come up with. a. M peak m/z- 74 b. M peak m/z 131 4. For each of the attached mass spectra 4A-H, a. Find and label the molecular ion (M) peak and indicate its m/z value. Record this in your notebook. b. Find and label the base peak and indicate its m/z value. Record this in your notebook c. Calculate the difference in mass (m/z) between the M peak and the base peak. What might be the structure of the radical fragment that was lost? d. Determine one or more plausible molecular formula(s) for each set of data and calculate the IHD for each. e. From the molecular formula(s) you determined above, suggest one or more plausible structures for each. 5. For each pair of MS and IR spectra 5A-D, a. Identify functional groups in the IR spectra b. Identify the M peak. c. Determine the molecular formula based on the M* and the functional groups in the IR. d. Propose a structure for each.

Answer 1

ay C& Hy → THD formula JHD 2(8) + 2-14 2 (n) +2 - No oft = 18-14 = 42 - 2 ns carbon H Hychogen I 18 -14 1 Structure :- 1) H ell -CH3 b), C3 H6 I HD 2(3)+2-6 = 3 = 1. Structure

2 C6 hs No . 2 (6)-(S-1+0) 12- 12-Sti+2 B45 Structure : d) Cy Hio Br₂ 2(7) - (10+2 +2 2 - 14 - 12+2 = - 12 - 2 22.

Structure 21-99