A naturally occurring element X is found to have exactly two isotopes, X-29 and X-31. A mass spectrometer produces a spectrum that is described as follows: the peak at m/z=29 has an area that is four times the area of the peak at m/z=31.
Answer the following questions about element X. Assume all ions detected are singly charged monatomic ions.
(a) Describe what information about the isotopic composition of element X can be inferred directly from the relative areas of the two peaks in the spectrum.
(b) Without performing a numerical calculation, explain why the weighted average atomic mass of element X must be closer to 29 amu than to 31 amu.
(c) Suppose a chemist enriches a sample so that the abundance ratio of X-29 : X-31 becomes 1.5 : 1. Predict qualitatively how the average atomic mass will change, and justify your prediction based on the definition of average atomic mass.