Question

1.The mass spectrum of a hypothetical element shows that 71.51% of the atoms have a mass of 27.977 u, 3.052% have a mass of 28.976 u, and the remaining have a mass of 29.974 u. Calculate the average atomic mass of this element (in units of u). (Use 4 Sig. Fig. Don't round until end.)

2.Bromine occurs naturally as two isotopes, one with a mass of 78.918 u and the other with a mass of 80.916 u. Suppose the average atomic mass from the periodic table were 80.83 u. What would be the percent abundance of the lighter isotope? (Use, 4 SIG. FIG.)

FYI (not useful for solving the problem) the actual mass and % abundance are 79.904 u and 50.65%, respectively.

3.

Answer 1