Calculate the formula masses of the following compounds:
(i) Sodium oxide, $N a_{2} O$
(ii) Aluminium oxide, $A l_{2} O_{3}$
(Given: Atomic masses : Na = 23 u; O = 16 u; Al = 27 u)

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Solution

(i) Mass of sodium oxide, $N a_{2} O$
Mass of ${N a}_{2}$ = 23 $\times$ 2 = 46u
Mass of O = 16u
Mass of ${N a}_{2}$ O = 46 + 16 = 62u

(ii) Mass of Aluminium oxide, $A l_{2} O_{3}$
Mass of ${A l}_{2}$ = 27 $\times$ 2 = 54u
Mass of $O_{3}$ = 16 $\times$ 3 = 48u
Mass of ${A l}_{2}$ O= 54 + 48 = 102u

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Calculate the formula masses of the following compounds: (i) Sodium oxide, Na2O (ii) Aluminium oxide, Al2O3 (Given: Atomic masses : Na = 23 u; O = 16 u; Al = 27 u)

(i) Mass of sodium oxide, Na2O Mass of Na2 = 23 × 2 = 46u Mass of O = 16u Mass of Na2O = 46 + 16 = 62u (ii) Mass of Aluminium oxide, Al2O3 Mass of Al2 = 27 × 2 = 54u Mass of O3 = 16 × 3 = 48u Mass of Al2O= 54 + 48 = 102u

Calculate the formula masses of the following compounds:
(i) Sodium oxide, $N a_{2} O$
(ii) Aluminium oxide, $A l_{2} O_{3}$
(Given: Atomic masses : Na = 23 u; O = 16 u; Al = 27 u)

(i) Mass of sodium oxide, $N a_{2} O$
Mass of ${N a}_{2}$ = 23 $\times$ 2 = 46u
Mass of O = 16u
Mass of ${N a}_{2}$ O = 46 + 16 = 62u

(ii) Mass of Aluminium oxide, $A l_{2} O_{3}$
Mass of ${A l}_{2}$ = 27 $\times$ 2 = 54u
Mass of $O_{3}$ = 16 $\times$ 3 = 48u
Mass of ${A l}_{2}$ O= 54 + 48 = 102u