Question

I will mark it as brainliest

Answer 1

It is exothermic reaction.

We do this because magnesium metal needs a source of energy.The flame provides a source of heat so that the magnesium metal atoms can overcome their activation energy. Activation energy is the minimum energy required in order for a chemical reaction to proceed. When the magnesium metal burns it reacts with oxygen found in the air to form Magnesium Oxide

Answer 2

Mg +O2 ------- MgO

It's a exothermic rxn. ( Hint- Almost all of the combination rxn are exothermic)