A mixture of 5L of H2 and 3L O2 reacts to form H2O (g) at constant T and P .Find the volume of H2O gas obtained. 2H2 (g) + O2(g)
2H2O(g)

The  volume of H₂O = 5 L

Given

5L of H₂ and 3L O₂

Reaction

2H₂ (g) + O₂(g)  ⇒2H₂O(g)

Required

The  volume of H₂O

Solution

Avogadro's hypothesis:  

In the same T,P and V, the gas contains the same number of molecules  

So the ratio of gas volume will be equal to the ratio of gas moles  

mol H₂ = 5, mol O₂ = 3

From equation, mol ratio H₂ : O₂ = 2 : 1, so :

mol H₂O based on mol H₂, and from equation mol ratio H₂ : H₂O=2 : 2, so mol H₂O = 5 mol and the volume also 5 L

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

the increase of protons   hope this