How much oxygen is needed to obtain 4 g of magnesium oxide?

Metallic magnesium is intensively oxidized by oxygen. The oxidation reaction is described by the following equation:

Mg + ½ O2 = MgO;

In this reaction, 1 oxygen atom is added to 1 magnesium atom and 1 molecule of magnesium oxide is synthesized.

Let’s determine the molar amount of magnesium.

Divide the available weight of magnesium oxide by the weight of 1 mole of this substance.

M Mg = 24 grams / mol; N Mg = 4/24 = 0.166 mol;

To burn such an amount of magnesium, 2 times less chemical amount of oxygen is required, which is 0.166 / 2 = 0.083 mol;

Let’s calculate its weight.

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

M O2 = 16 x 2 = 32 grams / mol; m O2 = 0.166 / 2 x 32 = 2.666 grams;