AS Chemistry mass spectra help?
How do I go about finding the answer to the following question?...
Bromine fluoride is unstable and readily gives Br19F3.
State the mass/charge(m/z) value for the molecular ion Br19F3+, when all the bromine is present as the isotope 85Br.
Comments
I would challenge this formula, Br19F3. Bromine does not have the bonding characteristics needed to form such large compounds. I sincerely doubt that a mass spectrometer would go up to a mass of over 16,700 amu for the BrF molecule. Furthermore, bromine-85 is a radioactive nuclide with a half'-life of about 3 minutes.
This whole problem doesn't make good scientific sense. By the time you perfomed the experiment the Br would have decayed by beta emission to Sr. The BrF molecule is an extremely reactive molecule. Are you sure that the formula of your compound is as stated. Perhaps you missed a decimal point and it is really Br1.9F3.
I think the 19 refers to the mass number of the fluorine atoms in this molecular ion.
Then the molecular ion contains three of these together with one bromine atom of mass number 85, and it has a single positive charge.
So, m/z = (85 + 19 + 19 + 19) / 1 = 142.
that's a user-friendly weighted straight forward> The mass is (0.39*179.ninety 4.. + 80 5.sixty seven*181.ninety 4.. + ......)/(0.39 + 80 5.sixty seven + 40 six.51 + a hundred + ninety 3.sixteen). look on the Menedleev table to verify the element.