Answer to Question #341584 in General Chemistry for Ddeonu

Question

Aluminum oxide has a composition of 52.9% aluminum and 47.1% oxygen by mass. If 16.4g of aluminum reacts with oxygen to form aluminum oxide, what mass of oxygen reacts?

 

Answer 1

The balanced chemical reaction is written as:

4Al + 3O₂ = 2Al₂O₃

To determine the mass of oxygen gas that would react with the given amount of aluminum metal, we use the initial amount and relate this amount to the ratio of the substances from the chemical reaction. We do as follows:

moles Al = 16.4 g ( 1 mol / 26.98 g ) = 0.61 mol Al

moles O₂ = 0.61 mol Al ( 3 mol O₂ / 4 mol Al ) = 0.46 mol O₂

mass O₂ = 0.46 mol O₂ ( 32.0 g / mol ) = 14.59 g O₂

Therefore, to completely react 16.4 grams of aluminum metal we need a minimum of 14.59 grams of oxygen gas.