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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)

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Give, the mass of Aluminum Oxide = 0.051 g.

The molecular mass of Aluminium Oxide = 2 x mass of Aluminium + 3 x mass of Oxygen.

                                                                  = 2 x 27 + 3 x 16

                                                                  = 102 g

Number of Moles of Aluminium Oxide :

frac0.051102=0.0005:moles

Now, Since 1 mole of Aluminium Oxide contain 2 moles of Aluminium ion,

The Number of Moles of Aluminium ion = 2 x number of moles of Aluminium Oxide 

                                                               =  2 x 0.0005

                                                               = 0.001 moles.

Now, As the number of ion in 1 mole = 6.022	imes10^23  ions.

The number of ions in 0.001 moles of Aluminium ion = 0.001	imes6.022	imes10^23 ions

                                                                                    = 6.022	imes10^20 ions.

Hence there are 6.022	imes10^20 Aluminium ions in 0.051 g of aluminium oxide.

Posted by

Deependra Verma

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