(Solved): 1. (4 pts) Calculate the isotopic distribution (both the mass and relative abundance) of \( \mathr ...

1. (4 pts) Calculate the isotopic distribution (both the mass and relative abundance) of \( \mathrm{CH}_{3} \mathrm{Cl} \) and \( \mathrm{CH}_{2} \mathrm{Cl}_{2} \). Note: only consider the major isotopes of \( \mathrm{C} \) (12 and 13) and \( \mathrm{Cl} \) (35 and 37). 2. (4 pts) Calculate the De Broglie wavelength of an electron in an El source (with 70 eV kinetic energy). Why do \( 70 \mathrm{eV} \) electrons provide an efficient ionization of molecules, considering this wavelength and a typical C-C bond length? 3. (4 pts) Below is an El mass spectrum of \( \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}=0 \). Please label those numbered peaks with the potential neutral losses and possible ion formulars. An example \( (\mathrm{m} / \mathrm{z} 71) \) has been given. Note: please pay attention to the OE or EE structures of ions.