2H2 + O2 --> 2H2O
How many grams of oxygen gas are required to produce 90. g of water?

80g

Explanation:

2H2 + O2 —> 2H2O

MM of H2O = (2x1) + 16 = 2 + 16 = 18g/mol

Mass conc. of H2O from the balanced equation = 2 x 18 = 36g

MM of O2 = 16 x 2 = 32g/mol

From the equation,

32g of O2 reacted to produce 36g of H2O.

Therefore Xg of O2 will react to produce 90g of H2O i.e

Xg of O2 = (32x90)/36 = 80g

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.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante