What volume of O2 gas, measured at 779 mmHg and 19 ∘C, is required to completely react with 53.7 g of Al? Express the volume in liters to three significant figures.

the answer to this question is 3.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.