If 24 grams of magnesium ($\text{Mg}$) react with 16 grams of oxygen ($\text{O}_2$​) to form magnesium oxide ($\text{MgO}$), what is the mass of the magnesium oxide formed?

To find the mass of magnesium oxide (MgO) formed, we need to consider the law of conservation of mass, which states that the total mass of the reactants must equal the total mass of the products in a chemical reaction.

The balanced chemical equation for the reaction between magnesium and oxygen to form magnesium oxide is:

$2\mathrm{Mg} + {\mathrm{O}}_2 \to 2\mathrm{MgO}$

The total mass of magnesium and oxygen:

24 grams of Mg + 16 grams of ${\mathrm{O}}_2$= 24 grams + 16 grams = 40 grams

Total mass of the reactants must equal the total mass of the products in a chemical reaction.

So, the total mass of the product is 40 grams.