Answer
3016.8 g or 3.0168 kg
Work Step by Step
We know, Density=$\frac{mass}{volume}$
Then mass=Density$\times volume$
Given Density=1.0056 $\frac{g}{cm^{3}}$
and volume=3 Liters
Volume should have the unit $cm^{3}$ since Density is in $\frac{g}{cm^{3}}$
1 Liter=1000 $cm^{3}$
3 Liters=3000 $cm^{3}$
Then mass=1.0056 $\frac{g}{cm^{3}}$ $\times 3000 $$cm^{3}$
=3016.8 g