General Knowledge Trivia Quiz
Counting gas particles with Avogadro
The name of physicist Amedeo Avogadro (1776-1856) is forever associated with “Avogadro’s number”, which arose from his famous hypothesis that, given equal conditions of temperature and pressure, the number of atoms or molecules in equal volumes of different gases is:
Your answer — B) Proportional to the atomic weights of the gases — was incorrect.
Avogadro put forward his hypothesis in 1811. It was a major contribution to the development of atomic theory, and has wide significance in chemistry and physics. Avogadro’s number, 6.022 x 1023, is the number of atoms or molecules in one mole of a gas. A mole is a quantity of a substance equal to its atomic mass (relative to that of hydrogen) in grams. A mole of helium, whose atomic mass is 4.003 times that of hydrogen, therefore weighs 4.003 gm.