Answer
$90 \%$
Work Step by Step
To calculate volume per cubic meter, use the formula
$V_{Na} = \frac{m N_A(4/3 \pi r^3)}{M_{Na}} $
Where
$m = 971kg$
$N_A$ is $6.022 \times 10^{23}/mol$
$r = 98 \times 10^{-12}m$
$M_Na = 23.0g/mol$
So,
$V_{Na} = \frac{(971kg)(6.022 \times 10^{23}/mol)4/3 \pi (98.0 \times 10^{-12}m)^3}{23.0g/mol} $
$V_{Na} = 0.100m^3$
Fraction available for conduction is
$1-(V_{Na}/1.00 m^3)$
$ = 1- 0.100 = 0.900 $
$ = 90.0\%.$
