Question

How much magnesium oxide will be formed when 192g of magnesium is burnt in the excess of air​

Answer 1

As air is excess, Mg is the limiting reagent.

2Mg + O2 ----> 2MgO.

Here 1 mol Mg gives 1 mol MgO.

Number of moles of Mg = 192/24= 8.

8 moles Mg gives 8 moles MgO.

Therefore, amount of MgO formed= 8×Molar mass of MgO = 8×40 = 320g.