Can someone ? i wasn't at school the day we did this and i don't understand.

1) 2700 kg/l
2) 13.6 kg/l
3) 0.1578 kg
4) 8921.5 kg/m3
5) 1.59 kg/l
6) 1.84 kg/l
7) 0.21965 kg
8) 11331.9 kg/m3
9) 7.9167 kg/l
10) 238.095 cm3

Just divide the masses by volume to find out the density, multiply the volume with density to find out the mass and divide the mass by density to find out the volume.
To turn the result into SI unit (kg/l), divide the g by 1000 and ml by 1000.