SolutionsBeginning of XIX Century
1. Avogadro's hypothesis
Two volumes of hydrogen and one of oxygen give two volumes of water vapour. Write the reaction and explain why hydrogen and oxygen molecules must be diatomic.
2 H2 + O2 → 2 H2O
According to Avogadro, equal volumes of gases contain the same number of molecules. If each oxygen molecule were a single atom, one volume of oxygen could not be shared out into two volumes of water. With O2, each molecule provides one atom to each of two water molecules.
2. Who and when?
Which chemist got Avogadro's hypothesis accepted, and in what year?
Stanislao Cannizzaro, in 1860.