Answer
The weight of the DNA molecule is 0.00094g
Work Step by Step
Conversion of the length of DNA from km to Å
Length of the DNA =(3,20,000 km) $\times$($10^{13}$ Å/km) = 32$\times$$10^{17} Å$
Conversion of the length of DNA from Å to bp
Number of base pairs = $\frac{32\times10^{17} Å}{3.4 Å/bp}$ = $94\times10^{16}$ bp
Weight of the DNA = $(94\times10^{16}bp)\times(\frac{10^{-8}g}{10^{3}bp})$ =0.00094g
