CHE 408 Home work March 14. 2018 Due March 21, 2018 1. An unknown hydrocarbon ha
ID: 1030126 • Letter: C
Question
CHE 408 Home work March 14. 2018 Due March 21, 2018 1. An unknown hydrocarbon has a molecular ion peak at m/z-84 with a relative intensity of 31.3. The M+1 peak has a relative intensity of 2.06 and the M+2 peak has a relative intensity of 0.08. What is the possible molecular formula of the compound? 2. The mass spectrum of an unknown liquid shows a molecular ion peak at m/z- 78 with a relative intensity of 23.6. The relative intensities of the isotopic peaks are: m/z 79 80 Relative intensit 1.00 7.55 0.25 What is the likely molecular formula of the unknown? 3. For each of the attached mass spectra a, b, c, and d, assign a structure of the compound that could give rise to the spectrum.Explanation / Answer
2. molecular ion m/z= 78
dividing 78 by the mass of 13C we get= 78/13=6
there are 6 carbons. so weight= 6*12= 72
remaining= 78-72=6
you have 6 Hs.
so your liquid most probably has the molecular formula of C6H6. benzene!
3. (a)