Answer
The salt concentration is $9.0~kg/m^3$
Work Step by Step
We can convert the salt concentration from $g/L$ to $kg/m^3$:
$(9.0~g/L)(\frac{10^{-3}~kg}{1~g})(\frac{10^3~L}{1~m^3}) = 9.0~kg/m^3$
Therefore, the salt concentration is $9.0~kg/m^3$.
