What charge does an object have that has lost an electron or electrons?

Assuming that the object started in the ground state, any object that has lost one or more electrons would have a positive change because there would be more protons than electrons present. Therefore, the positive charge of the protons would preside over the negative change of the electrons.  

Hope this helps.

30litre of li2o is 1.0002mole approximately 1 mole

The density would be 1.622