Question

T O U ME Spectra by McLafferty and Turacek 113, ISBN 978-0935702255). this book is a classic in the field. Read the text and propose answers for Unknowns 1.1.1.2. and 1.3.(page 5 of this handout contains an for the spectroscopic data) 1.1 Appearance of the mass spectrum Learning how to identify a simple molecule from its electron-ionization (ET) mass spectrum is much easier than from other types of spectra. The mass spec. trum shows the mass of the molecule and the masses of pieces from it. Thus the chemist does not have to learn anything new-the approach is similar to an arithmetic brain-teaser. Try one and see. Unknown 1.1 18= base peak and parent Relative intensity Mass = 18 muz 2013 mass to charge ratio In the bar-graph form of a spectrum (as in that for Unknown 1.1), the abscissa indicates the mass (actually m/z, the ratio of mass to the number of charges on the ions employed), and the ordinate indicates the relative intensity. If you need a hint, remember that the atomic weights of hydrogen and oxygen are 1 and 16, respectively. Check your answer (the solutions to the unknowns are given in Chapter 11). Page 3 of 1

Answer 1

m/z = 18 suggests that peak in mass spectrum corresponds to H2O. mass of water = 18 g/mol (2x1+18)