Changes

: The [[Relative Atomic Mass|relative atomic mass]] of an [[element]] is the [[mass]] of 1 [[mole]] or the [[mass]] of 6.02x10²³ [[atom]]s. So 1g of [[Hydrogen]] is 1 [[mole]] and contains 6.02x10²³ [[atom]]s. 235g of [[Uranium-235]] is 1 [[mole]] and contains 6.02x10²³ [[atom]]s.

Number of [[Mole]]s of an [[Element]] = ([[Mass]] of [[Element]])/([[Relative Atomic Mass]] of [[Element]])

M_r = The [[Relative Formula Mass]] of the [[compound]]