The Student Room Group

A Chem question im confused with

4. The maxx spectrum of X2 has peaks at the following m/z values for the X +
Ion.
32, 33, 34, 35, 36
Deduce the formula of all the species responsible for each peak in the mass spectrum of X2.
Identify the element X2 and list all the isotopes present.
The mass spectrum of X2 showing peaks at m/z values of 32, 33, 34, 35, and 36 suggests that X2 is a diatomic molecule composed of an element with multiple isotopes.
1. m/z = 32: This is likely the most abundant isotope, as lower m/z values usually correspond to more abundant isotopes. Since this is a diatomic molecule (X2), each atom of X would have a mass of 16. The most common isotope with an atomic mass of 16 is 16O (Oxygen). However, Oxygen does not have isotopes that would match the other m/z values exactly, so we must consider other elements.
2. m/z = 33: This suggests an isotope of X with an atomic mass of 16.5. However, since atomic masses are integers, this peak likely represents a molecule with one atom of X being the most abundant isotope (from the m/z 32 peak) and the other being a heavier isotope.
3. m/z = 34: This could represent a molecule where both atoms are of a heavier isotope than the most abundant one. Another possibility is the presence of an isotope of X with an atomic mass of 17.
4. m/z = 35 and 36: These peaks suggest even heavier isotopes of X.
Given these considerations, a likely candidate for X is Sulphur (S), which has several isotopes that can account for the observed m/z values in the mass spectrum of S2. Sulphur's most common isotope is 32S, and it also has isotopes like 33S, 34S, and 36S, which can combine in various ways to give the observed m/z values.
Therefore, the element X is most likely Sulphur S, and the isotopes present are 32S, 33S, 34S, 36S.
(edited 4 months ago)
Original post by SilverPebble
The mass spectrum of X2 showing peaks at m/z values of 32, 33, 34, 35, and 36 suggests that X2 is a diatomic molecule composed of an element with multiple isotopes.
1. m/z = 32: This is likely the most abundant isotope, as lower m/z values usually correspond to more abundant isotopes. Since this is a diatomic molecule (X2), each atom of X would have a mass of 16. The most common isotope with an atomic mass of 16 is 16O (Oxygen). However, Oxygen does not have isotopes that would match the other m/z values exactly, so we must consider other elements.
2. m/z = 33: This suggests an isotope of X with an atomic mass of 16.5. However, since atomic masses are integers, this peak likely represents a molecule with one atom of X being the most abundant isotope (from the m/z 32 peak) and the other being a heavier isotope.
3. m/z = 34: This could represent a molecule where both atoms are of a heavier isotope than the most abundant one. Another possibility is the presence of an isotope of X with an atomic mass of 17.
4. m/z = 35 and 36: These peaks suggest even heavier isotopes of X.
Given these considerations, a likely candidate for X is Sulphur (S), which has several isotopes that can account for the observed m/z values in the mass spectrum of S2. Sulphur's most common isotope is 32S, and it also has isotopes like 33S, 34S, and 36S, which can combine in various ways to give the observed m/z values.
Therefore, the element X is most likely Sulphur S, and the isotopes present are 32S, 33S, 34S, 36S.

"Given these considerations, a likely candidate for X is Sulphur (S), which has several isotopes that can account for the observed m/z values in the mass spectrum of S2. Sulphur's most common isotope is 32S, and it also has isotopes like 33S, 34S, and 36S, which can combine in various ways to give the observed m/z values."

You cannot combine isotopes in a mass spectrum, unless they are multi atom particles. But as you are told that it is X+ then you know that this is not a multi-atom species.

Your suggestion that it is sulfur is correct and the 35S+ isotope is responsible for the peak at 35
(edited 4 months ago)

Quick Reply

Latest