Developement of avogadro's number/mole concept?
All I know is that he made the avogadro's number.
6.022 x 10^23 atoms
I have no idea how he calculated that. That is suppose to be the number of atoms in 1 mole of an element.
Are you looking for someone to derive this number? Look in your texts. Most chemistry and physics texts have it.
The development of Avogadro's number and the concept of a mole involved significant contributions from several scientists over time. This explanation will provide an overview of the key milestones in their development.
1. Early Atomic Theory:
- In the early 19th century, John Dalton proposed the atomic theory, suggesting that elements consist of tiny, indivisible particles called atoms.
- Dalton further suggested that atoms combine in fixed ratios to form compounds, laying the groundwork for the understanding of chemical reactions.
2. Law of Combining Volumes:
- In 1808, Joseph Louis Gay-Lussac observed that gases react with each other in simple whole number ratios.
- Gay-Lussac's Law of Combining Volumes provided early empirical evidence for the idea of a fixed ratio between atoms that combine to form compounds.
3. Avogadro's Hypothesis:
- In 1811, Amedeo Avogadro proposed a hypothesis to reconcile the observed combining volumes with Dalton's atomic theory.
- Avogadro hypothesized that equal volumes of gases under the same conditions of temperature and pressure contained an equal number of particles (atoms/molecules), regardless of their nature.
- This idea was contrary to the prevailing belief that the volume of a gas depended solely on the number of atoms or molecules present.
4. Avogadro's Number:
- The concept of Avogadro's number, representing the number of particles (atoms, molecules, ions, etc.) in one mole of a substance, was introduced much later.
- The actual numerical value of Avogadro's number (approximately 6.022 x 10^23) was determined through experimental measurements by Jean Baptiste Perrin in the early 20th century.
- Perrin used the technique of sedimentation to accurately measure the number of particles in a given volume of a suspension.
5. Acceptance of Avogadro's Hypothesis:
- Despite Avogadro's hypothesis being proposed in 1811, it faced resistance and skepticism for several decades.
- It was not until the 1860s that the scientific community began to widely accept Avogadro's hypothesis, largely due to the work of Stanislao Cannizzaro.
- Cannizzaro presented a comprehensive paper on Avogadro's hypothesis at an international conference in 1860, elucidating its significance and providing a precise methodology for determining atomic masses and formulas of compounds.
In summary, the development of Avogadro's number and the mole concept involved the contributions of several scientists and their observations, hypotheses, and experimental work. Avogadro's hypothesis, proposing the equal volumes of gases contain an equal number of particles, laid the foundation for understanding the relationship between atoms and molecules. Eventually, Avogadro's number was determined experimentally, solidifying the concept of the mole and enabling precise calculations in chemistry.