The density is still rho. It doesn't change. The density of a substance is the density of the substance. It doesn't depend on how much of it you have.
Answer:
B
Explanation:
Density = mass / volume
Less dense objects float to the surface so if the liquid becomes 1000 kg/m3 then it is the densest thing in the mixture, except for Q which has a density = to that of the water so it will stay in place around the middle, since the other two are more dense they will go to the bottom of the container.
When oxygen reacts with magnesium thenMgO3 is formed.
Mg +O2----> MgO3