Question

calculate the number of molecules of aluminium ions present in 0.051 g of aluminum oxide.

Answer 1

no. of molecule = moles multiply 6.022 multiply 10^23
Aluminium oxide
Al O
+3 -2
Al ^2 downwards O ^3 downwards
27 multiply 2 + 16 multiply 3
54 + 48 = 102 u
0.051/ 102 multiply 6.022 multiply 10^23
= 3.011 multiply 10 ^22