How many grams of magnesium oxide forms when 8.0g of magnesium are burned?

Magnesium burns with oxygen to give magnesium oxide based on the following reaction:

2M g + O 2 ... > 2Mg O (s) + energy

From the periodic table:

molecular mass of magnesium = 24.3 grams

molecular mass of oxygen = 16 grams

From the reaction:

2 x 24.3 = 48.6 grams of magnesium are required to produce 2 (24.3+16) = 80.6 grams of magnesium oxide.

We can know the amount of magnesium oxide produced from 8 grams of magnesium by simply doing cross multiplication as follows:

amount of magnesium oxide = (8 x 80.6) / 48.6 = 13.267 grams