Calculate the mass of the oxide that forms when 7.2 grams of magnesium reacts with oxygen.

Metallic magnesium reacts intensely with oxygen. The oxidation reaction is described by the following equation:

Mg + ½ O2 = MgO;

During oxidation, 1 oxygen atom is attached to the magnesium atom and 1 molecule of magnesium oxide is synthesized.

Let’s calculate the chemical (molar) amount of magnesium.

To do this, divide the available weight of magnesium by the weight of 1 mole of this substance.

M Mg = 24 grams / mol; N Mg = 7.2 / 24 = 0.3 mol;

During the reaction, the same amount of magnesium oxide will be synthesized.

Let’s determine its weight.

Let’s multiply the molar amount of the substance and the weight of 1 mole of the substance.

M MgO = 24 + 16 = 40 grams / mol; m MgO = 0.3 x 40 = 12 grams;