Calculate the number of moles present in:

CBSE Class 9 CBSE Class 9 Science
,
1

Calculate the number of moles present in:
(i) 3.011 x ${10}^{23}$ number of oxygen atoms
(ii) 60 g of calcium
[Given that atomic mass of = 40 u and
Avogadro’s number = 6.022 x ${10}^{23}$]

2

(i)Number of moles = Given number of atoms / Avagadro’s number
Number of atoms in oxygen molecule = 3.011 x ${10}^{23}$ / 6.022 x ${10}^{23}$ = 0.5 moles.
(ii) Number of moles 60 g of calcium = Given mass / molar mass = 60/40 = 1.5 moles.