(a) Define Avogadro's number. Why is it also known as Avogadro's constant?
(b) Calculate the molar mass of `Na_(2)O`.
(c) Find the mass of 10 moles of carbon dioxide.

Explanation

(a) Avogadro's number is the number of particles (atoms, ions, molecules etc) present in one mole of any substance. It is denoted either as `N_(A)` or as No. The number is also called Avogadro's constant because its value is fixed `(6.022 xx 10^(23))` irrespective of the nature of the particles.
(b) `"Molar mass of "Na_(2)O= 2 xx "Atomic mass of Na"+"Atomic mass of O"=2 xx 23u+16u =62u`
(c )Mass of 10 moles of `CO_(2)=10xx44=440u`