An aqueous solution of volume 7 dm3 is obtained by dissolving 5.5 kg of C12H22O11 in enough water. express the concentration in mol/L and mol/Kg

5.5 kg = 5,500 g.

mols = grams/molar mass
mols/L and mols/kg. Technically you can't do mols/kg unless you know the density. I suppose you are to assume the density of ther solution is 1 g/mL.