Compound $$$\mathbf{W}$$$ has molecular formula $$$\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}$$$. It contains only one functional group. Table 5.1 shows the two peaks with the greatest $$$\mathrm{m} / \mathrm{e}$$$ values in the mass spectrum of $$$\mathbf{W}$$$. (i) Calculate the relative abundance, x , of the peak at $$$m / e=75$$$ using the information from Table 5.1. $$\[ x= \]$$ .......................... (ii) The mass spectrum of $$$\mathbf{W}$$$ also shows peaks at $$$m / e=29$$$ and $$$m / e=59$$$. Suggest the molecular formulae of these fragments. = 29 .......................... = 59 ..........................

Chemistry

IGCSE&ALevel

CAIE

Exam No：9701_s24_qp_22 Year：2024 Question No：5(a)

Answer:

22.2.1 analyse mass spectra in terms of m/e values and isotopic abundances (knowledge of the working of the mass spectrometer is not required)

22.2.2 calculate the relative atomic mass of an element given the relative abundances of its isotopes, or its mass spectrum

22.2.3 deduce the molecular mass of an organic molecule from the molecular ion peak in a mass spectrum

22.2.4 suggest the identity of molecules formed by simple fragmentation in a given mass spectrum

22.2.5 deduce the number of carbon atoms, n, in a compound using the M +1 peak and the formula

22.2.6 deduce the presence of bromine and chlorine atoms in a compound using the M +2 peak