34. Using Eq. 43-14 and Eq. 43-17 (and the fact that mass is proportional to the number of atoms), the
amount decayed is
|"m| = m|t =16.0h - m|t =14.0h
f i
i f
= m0(1 - e-t ln 2/T1/2) - m0(1 - e-t ln 2/T1/2)
f i
= m0(e-t ln 2/T1/2 - e-t ln 2/T1/2)

= (5.50 g) e-(16.0h/12.7h)ln2 - e-(14.0h/12.7h)ln2
= 0.256 g .