How much magnesium must be burnt in oxygen to obtain 1kg of magnesium oxide

1. The reaction of burning of Magnesium in presence of Oxygen to give Magnesium Oxide is as follows:

     2 Mg(s) + O₂(g) $\to$ 2 MgO (s)

2. 2 moles of Mg give 2 moles of MgO.

Number of moles in 1kg of MgO = $\frac{Given mass}{Molar mass}=\frac{1000}{40.3}= 24.8 moles (1kg = 1000g)$

3. So, 24.8 moles of Mg is required.

 So mass of Mg in 24.8 moles = $$\begin{gathered} Number of moles \times Molar mass \\ = 24.3 \times 24.3 = 590 g = 0.59 g \end{gathered}$$