Please help with chemistry? I don't know what I'm doing!?

Question

Hydrogen and chlorine both have two naturally occurring isotopes:1H(1.0078 amu; 99.985% abundance) and 2H(2.01410 amu; 0.015%abundance), 35Cl(34.969 amu; 75.53% abundance) and 37Cl (36.966 amu; 24.47% abundance).

(A) How many peaks would be expected in a mass spectrum of HCl?

(B) At what molecular weights will peaks be observed?

(C)What should be the relative intensities of the peaks?

If anyone could help that would be awesome. Thanks

Answer 1

(A) How many peaks would be expected in a mass spectrum of HCl?

four

(B) At what molecular weights will peaks be observed?

HCl from H-1 & Cl- 35: (36 amu ...  35.977 amu)

HCl from H-1 & Cl- 37: (38 amu ... 37.974 amu)

HCl from H-2 & Cl- 35: (37 amu ... 36.983 amu)

HCl from H-2 & Cl- 37: (39 amu ... 38.980 amu)

(C)What should be the relative intensities of the peaks?

HCl from H-1 & Cl- 35: (99.985 % of 75.53%) = 75.52%

HCl from H-1 & Cl- 37: (99.985% of 24.47%) = 24.47%

HCl from H-2 & Cl- 35: (0.015% of 75.53%) = 0.011%

HCl from H-2 & Cl- 37: (0.015% of 24.47%) = 0.0036%

that's the answers rounded off to the # of allowed sig figs

(C)What should be the relative intensities of the peaks?