Chemistry Problem

Question

Hydrogen and chlorine each 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(g)? (b) At what molecular weights will peaks be observed? (c) What should be the relative intensities of the peaks?

Answer 1

a)¹H³⁵Cl, ¹H³⁷Cl, ²H³⁵Cl and ²H³⁷Cl = 4 peaks

b) 35, 36, 37 and 38

c) 36 will be largest; 38 next largest; 35 next largest and 37 smallest.  To calculate actual values, use % abundance.