Magnesium reacts with oxygen to form two compounds. Compound A contains 7.88 g of magnesium for every 15.68 g of oxygen. Compound B contains 2.12 g of magnesium for every 6.91 g of oxygen. What is the mass ratio of magnesium rounded to the nearest whole number

Mass ratio of magnesium =  2 : 1

Explanation:

Let us write down the masses of element involve to form the compounds .

Compound A → 7.88 g of mg and 15.68 g of 02

Compound B → 2.12 g of mg and 6.91 g of 02

since we want to get the mass ratio of magnesium, we divide the mass of mg with the other element present (oxygen) . we want to make both compound in equal proportions.

Compound A →  7.88 / 15.68  = 0.5025510204 g of Mg /1 g of Oxygen

Compound B  →  2.12 / 6.91  = 0.30680173661  g of Mg/ 1 g of Oxygen

Mass ratio of magnesium = compound A(Mg)/compound B(Mg)

Mass ratio of magnesium = 0.5025510204/0.30680173661  

Mass ratio of magnesium = 1.63803186368 /1

Mass ratio of magnesium =  2 : 1