Home NCERT Solutions NCERT Exemplar CBSE Sample Papers NCERT Books Class 12 Class 10
Question 11

Calculate the number of aluminium ions present in 0.051 g of aluminium oxide.
(Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)

Answer

Molar Mass of Al2O3 = 2 x Atomic mass of Al + 3 x Atomic mass of O
    = 2 x 27 + 3 x 16
    = 54 + 48 = 102 g 

102 g of Al2O3 contain = 2 x 6.022 x 1023 aluminium ion
   = 0.051 g of Al2O3 = 2 x 6.022 x 1023 / 102 x 0.051
   = 6.022 x 1023 x 10-3 = 6.022 x 1020

Popular Questions of Class 9 Science

Write a Comment: