Write a brief paragraph to answer the following question. Around 1805, Gay-Lussac and von Humboldt determined that two volumes of hydrogen and one volme of oxygen, were needed to form two volumes of water. Later around 1811 Avogadro had arrived at the conclusion that hydrogen and oxygen must be diatomic molecules even though the concept of a mole was not developed until 1900. How did Avogadro figure this out