CHEM 238 Exam 2 Questions and Answers Solved Correctly Latest Update 2025
IR - Answers Uses IR light to show strength of the bond
IR graph - Answers X: wavenumber (cm-1) (larger the number the larger the energy absorbed)
Y: percent transmittance (larger more absorbance)
IR trends - Answers Weight increases, wavenumber decreases
Bond strength increases, wavenumber increases
Number of bonds increases, peak size increases
Bond polarity increases, peak size increases
Fingerprint region - Answers Region below 1500 that is unique for every molecule
Mass Spectrometry - Answers Measures molecular weight by ionizing the sample and measuring the
mass to charge
Mass Spec graph - Answers X: m/z ratio
Y: Intensity (relative abundance)
Tallest peak is the base peak
Parent peak (M) is the peak that corresponds to the unfragmented radical cation
Peaks above M are due to isotopes
Fragment peak - Answers Stable carbocation
Cl - Answers will have two equally intense peaks at M and M+2
Br - Answers will have two equally intense peaks at M and M+2
Nitrogen - Answers Odd number of nitrogen, odd mass
IR - Answers Uses IR light to show strength of the bond
IR graph - Answers X: wavenumber (cm-1) (larger the number the larger the energy absorbed)
Y: percent transmittance (larger more absorbance)
IR trends - Answers Weight increases, wavenumber decreases
Bond strength increases, wavenumber increases
Number of bonds increases, peak size increases
Bond polarity increases, peak size increases
Fingerprint region - Answers Region below 1500 that is unique for every molecule
Mass Spectrometry - Answers Measures molecular weight by ionizing the sample and measuring the
mass to charge
Mass Spec graph - Answers X: m/z ratio
Y: Intensity (relative abundance)
Tallest peak is the base peak
Parent peak (M) is the peak that corresponds to the unfragmented radical cation
Peaks above M are due to isotopes
Fragment peak - Answers Stable carbocation
Cl - Answers will have two equally intense peaks at M and M+2
Br - Answers will have two equally intense peaks at M and M+2
Nitrogen - Answers Odd number of nitrogen, odd mass
