Can Someone explain why this is wrong please?

You have taken unit for mass as grams.
Converted mass:-
[tex]\\ \sf\longmapsto 2752.512g[/tex]
Hence our and should be
[tex]\\ \sf\longmapsto 2.752kg[/tex]
Answer:
Step-by-step explanation:
Volume of the cube:
Mass:
Your answer is correct