Answer
$M_{total} = 1.11 \times 10^{-7} g $
Work Step by Step
The mass of a single $^{56}Mn$ nucleus is
$m = (56 u) (1.661 \times 10^{–24} g/u) $
$ m = 9.30 \times 10^{–23} g$
And the total mass must be multiplied by number of nuclei, N
$M_{total} = (1.19 \times 10^{15})(9.30 \times 10^{–23} g)$
$M_{total} = 1.11 \times 10^{-7} g $
