Question

How many grams of magnesium oxide are obtained during the combustion of 1 g of magnesium in air according to the reaction 2Mg (s) + O₂ (g) -> 2MgO (s). Ar(Mg) = 24.3; Ar(O) = 16

Answer 1

Moles of $Mg=\frac{2}{24.3}=0.082moles$

Ratio of $Mg$ and $MgO= 2:2$

Hence moles of of $MgO=$ $0.082moles$

Molar mass of $MgO=24.3+16=40.3$

Mass of $MgO=40.3×0.082=3.3046grams$