Textbooks need an update after mole's definition changed

‘A mole contains as many elementary entities as there are atoms in 12g of carbon-12’ is what many chemists – and schoolchildren – would say when asked to define a mole. But this textbook definition is now set to be rewritten as the International Union of Pure and Applied Chemistry (Iupac) has redefined the mole. Iupac’s new definition relies solely on a fixed value of the Avogadro constant and describes the mole as containing exactly 6.02214076x10²³ elementary entities.