How would you answer this? I don't really understand molecular ions
assuming that chlorine exists as 2 isotopes, and that hydrogen and carbon exist as 1 isotope each, how many molecular ion peaks will be shown in the mass spectrum of C4H6Cl4?
chlorine has 2 isotopes. the number of molecular ion peaks in the mass spec of Cl2 is:
I don't really understand molecular ionsassuming that chlorine exists as 2 isotopes, and that hydrogen and carbon exist as 1 isotope each, how many molecular ion peaks will be shown in the mass spectrum of C4H6Cl4?
chlorine has 2 isotopes. the number of molecular ion peaks in the mass spec of Cl2 is:
assuming that chlorine exists as 2 isotopes, and that hydrogen and carbon exist as 1 isotope each, how many molecular ion peaks will be shown in the mass spectrum of C4H6Cl4?
chlorine has 2 isotopes. the number of molecular ion peaks in the mass spec of Cl2 is:
Molecular ion is just - it's the whole molecule - no fragmentation, just the loss of an electron.
Chlorine has two isotopes, Cl35 and Cl37; so in a compound containing one chlorine compound there's two molecular ions; M and M+2: one where the chlorine is Cl35 and one where it's Cl37. For dichloro- compounds you've got the M+4 where both chlorines are Cl37 in addition to the M and M+2. Likewise trichloro- compounds have an M+6 peak (all three the heavier isotope), and tetrachloro- compounds will have an M+8 peak in addition to the others. So C4H6Cl4 has five molecular ions. M; M+2; M+4; M+6 and M+8; giving five molecular ion peaks, although the intensities of the higher peaks will be a lot lower due to the relative abundance of Cl35 compared to Cl37.
Molecular ion is just - it's the whole molecule - no fragmentation, just the loss of an electron.
Chlorine has two isotopes, Cl35 and Cl37; so in a compound containing one chlorine compound there's two molecular ions; M and M+2: one where the chlorine is Cl35 and one where it's Cl37. For dichloro- compounds you've got the M+4 where both chlorines are Cl37 in addition to the M and M+2. Likewise trichloro- compounds have an M+6 peak (all three the heavier isotope), and tetrachloro- compounds will have an M+8 peak in addition to the others. So C4H6Cl4 has five molecular ions. M; M+2; M+4; M+6 and M+8; giving five molecular ion peaks, although the intensities of the higher peaks will be a lot lower due to the relative abundance of Cl35 compared to Cl37.
What about the carbon and hydrogen? I understand what you're saying but what do you mean by M+ and M+2 etc.
What about the carbon and hydrogen? I understand what you're saying but what do you mean by M+ and M+2 etc.
You're told to assume that carbon and hydrogen only have 1 isotope; so there's only one potential molecular weight for them.
M is the molecular ion; the mass of the molecule (assuming chlorine is present solely as Cl35) M+2 is that plus 2 mass units - assuming that one of the chlorines is Cl37 since Cl37 is two mass units heavier than Cl35. M+4 is the mass of the molecule plus 4 mass units, assuming 2 chlorines are the heavier isotope. M+6 is mass + 6 mass units for 3 of the heavier chlorine isotope, and so on.
You're told to assume that carbon and hydrogen only have 1 isotope; so there's only one potential molecular weight for them.
M is the molecular ion; the mass of the molecule (assuming chlorine is present solely as Cl35) M+2 is that plus 2 mass units - assuming that one of the chlorines is Cl37 since Cl37 is two mass units heavier than Cl35. M+4 is the mass of the molecule plus 4 mass units, assuming 2 chlorines are the heavier isotope. M+6 is mass + 6 mass units for 3 of the heavier chlorine isotope, and so on.
so M+4 is Cl37 and Cl37 ? Back to the original ques, so the compound contains Cl4: M + M+2 and ??? I'm confused :'( I still don't understand
please could you write out the combinations like cl35 and cl37 because I don't understand M and M+2. sorry for causing you trouble
Sure:
M - 4 x Cl35 M+2 - 3 x Cl35; 1 x Cl37 M+4 - 2 x Cl35; 2 x Cl37 M+6 - 1 x Cl35; 3 x Cl37 M+8 - 4 x Cl37
So M would be with the chlorines contributing 140 m.u. to the weight of the molecular ion. M+2 has chlorine contributing 142 m.u. thanks to the extra 2 m.u. from the heavier isotope. M+4 has the chlorines at 144 m.u., 2 extra m.u. from each of the chlorine, a total of 4 extra m.u. etc.
M - 4 x Cl35 M+2 - 3 x Cl35; 1 x Cl37 M+4 - 2 x Cl35; 2 x Cl37 M+6 - 1 x Cl35; 3 x Cl37 M+8 - 4 x Cl37
So M would be with the chlorines contributing 140 m.u. to the weight of the molecular ion. M+2 has chlorine contributing 142 m.u. thanks to the extra 2 m.u. from the heavier isotope. M+4 has the chlorines at 144 m.u., 2 extra m.u. from each of the chlorine, a total of 4 extra m.u. etc.
Thanks. so what would it be for Cl4 - I might ask my teacher to explain this to me as I don't get molecular ions as a whole
Chlorine has two isotopes, Cl35 and Cl37; so in a compound containing one chlorine compound there's two molecular ions; M and M+2: one where the chlorine is Cl35 and one where it's Cl37. For dichloro- compounds you've got the M+4 where both chlorines are Cl37 in addition to the M and M+2. Likewise trichloro- compounds have an M+6 peak (all three the heavier isotope), and tetrachloro- compounds will have an M+8 peak in addition to the others.
So C4H6Cl4 has five molecular ions. M; M+2; M+4; M+6 and M+8; giving five molecular ion peaks, although the intensities of the higher peaks will be a lot lower due to the relative abundance of Cl35 compared to Cl37.
assuming that chlorine exists as 2 isotopes, and that hydrogen and carbon exist as 1 isotope each, how many molecular ion peaks will be shown in the mass spectrum of C4H6Cl4?
The molecular ion is the one at m/z 194 - the molecular weight of C4H6Cl4 if the Cls were of mass 35. You're told that hydrogen and carbon are there as one isotope, so you can discount the effects of different isotopes of those into the peaks; and you're told that there are 2 isotopes of chlorine. So the simplified question you're actually answering is how many different combinations of Cl35 and Cl37 (the two chlorine isotopes) are possible?
chlorine has 2 isotopes. the number of molecular ion peaks in the mass spec of Cl2 is:
Again the molecular ion is the one at the m/z of Cl2 - there's two isotopes of chlorine, in how many ways could they combine in Cl2?
The molecular ion is the one at m/z 194 - the molecular weight of C4H6Cl4 if the Cls were of mass 35. You're told that hydrogen and carbon are there as one isotope, so you can discount the effects of different isotopes of those into the peaks; and you're told that there are 2 isotopes of chlorine. So the simplified question you're actually answering is how many different combinations of Cl35 and Cl37 (the two chlorine isotopes) are possible?
Different combinations of the 2 isotopes in Cl4: 5? so:
4 x Cl35 4 x Cl37 3 x Cl35 and Cl37 3 x Cl37 and Cl35 2 x Cl35 and 2 x Cl37
I know that you discount carbon and hydrogen because they only exist as 1 - but why?
Again the molecular ion is the one at the m/z of Cl2 - there's two isotopes of chlorine, in how many ways could they combine in Cl2?