Because it is a pure substance, and it will not change because it has nothing mixed with it. When things get mixed, amounts vary, but it's on its own so everything stays the same.
Conductions is batteries because it’s a battery and it can use e gweh
The dalton or unified atomic mass unit is a unit of mass widely used in physics and chemistry. It is defined as 1⁄12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted mᵤ is defined identically, giving mᵤ = m/12 = 1 Da.