Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
Scientists expected that the law of conservation of mass would apply to nuclear fission in terms of the masses of the subatomic particles. In reality, the mass of an atom is not equal to the sum of the masses of the subatomic particles that make it up. This is because of the energy that binds the subatomic particles. This energy has mass and when the bond is broken, the mass of the energy of the bonds is lost resulting to what we now cal, a mass defect.
Use your periodic table to get 1 mol. Look up the atomic masses. I'll round the numbers since every periodic table is different.
N = 14
O2 = 2 *16
Total = 30 grams / mol
Therefore 2 mols = twice as much = 60 grams.
