Which of the following is the correct equation for the reaction below?
Two molecules of magnesium solid react with one molecule of oxygen gas to
form two molecules of magnesium-oxide solid.
O A. Mg(s) + O2(g) → Mgo (s)
O B. 2 Mg (9) + O2(g) → 2 Mgo (9)
O C. 2 Mg (s) + O2 (g) – 2 Mgo (s)
O D. 2Mg2 (s) + 20 (g) – 2MgO2 (s)

Option C.

2 Mg (s) + O₂(g) →  2MgO (s)

Explanation:

Two moles of magnesium solid react with one mol of oxygen gas to

form two moles of magnesium-oxide solid

2 Mg (s) + O₂(g) →  2MgO (s)

That's the reaction for the magnessium oxide's formation.

Be careful cause we do not say molecules, they are moles.

The stoichiometry indicates the number of moles that react and the moles which are produced.

It is a redox reaction, because the magnessium is oxidized and the oxygen is reduced. Both elements, changed the oxidation states.