First, you need to know 1 kg = 10^3 g. And 1 m^3 = 10^6 m^3. So the 1 g/cm3 = 10^3 kg/m3. So the answer is 1.93*10^4 kg/m3.
Its the complete transfer of valence electrons between atoms
A physical change has occured, Boiling water is a physical change not a chemical one, now if you're talking about the electric current, that had not changes either. it may rearrange the molecules, but it does not change the fundamental properties of the substance.