Question

A student decomposes water vapor into its elements. What volume of oxygen would be formed under the same conditions as the water vapor, if 5.0 L was decomposed?

a) 2.5 L
b) 5.0 L
c) 7.5 L
d) 10.0 L

Answer 1

The volume of oxygen formed from the decomposition of 5.0 L of water vapor, under the same conditions of temperature and pressure, would be 2.5 L.

Step-by-step explanation:

When decomposing water vapor into hydrogen and oxygen, the balanced chemical reaction is 2H₂(g) + O₂(g) → 2H₂O(g). This means that two volumes of hydrogen gas react with one volume of oxygen gas to produce two volumes of water vapor. If we start with 5.0 L of water vapor, keeping in mind the stoichiometry of the reaction, we would have half that volume of oxygen gas since water produces oxygen and hydrogen in a 2:1 ratio. Therefore, the correct volume of oxygen that would form under the same conditions of temperature and pressure would be half of the water vapor volume, which is .