I’m assuming you mean 5g of magnesium :)
The answer is: hydrogen peroxide, H2O2.
H₂O₂(hydrogen peroxide) is pale blue, clear, inorganic liquid.
It is liquid because hydrogen bonds between molecules.
Hydrogen bond is an electrostatic attraction between two polar groups that occurs when a hydrogen atom (H), covalently bound to a highly electronegative atom such as flourine (F), oxygen (O) and nitrogen (N) atoms.
Because of hydrogen bonds, hydrogen peroxide has higher melting and boiling temperatures than other molecules.
In normal conditions, warm water does "pile up" in the" Western Pacific Ocean.
The chemical change can occur can be find if you mix the two solids in one direction
