3/28/2024 0 Comments Periodic table molar mass of h20While these early estimates have since been refined, they led to the concept of the mole - that is, the theory that in a defined mass of an element (its atomic weight) there is a precise number of atoms: Avogadro's number. Building on this work, an Austrian high school teacher named Johann Josef Loschmidt calculated the size of a molecule of air in 1865, and thus developed an estimate for the number of molecules in a given volume of air. About fifty years later, an Italian scientist named Stanislao Cannizzaro used Avogadro's hypothesis to develop a set of atomic weights for the known elements by comparing the masses of equal volumes of gas. Amedeo Avogadro was an Italian physics professor who proposed in 1811 that equal volumes of different gases at the same temperature contain equal numbers of molecules. The number of objects in one mole, that is, 6.02 x 10 23, is commonly referred to as Avogadro's number. Instead of talking about trillions and quadrillions of molecules (and more), it's much simpler to use the mole. A drop of water the size of the period at the end of this sentence would contain 10 trillion water molecules. Atoms and molecules are very tiny things. The mole is used when we're talking about numbers of atoms and molecules. So why would we ever use such a big number? Certainly the local donut store is not going to "supersize" your dozen by giving you a mole of jelly-filled treats. You can see that The molar mass of Hydrogen is 1.008 g/mol. So let’s look at the molar mass of Hydrogen and Fluorine from the above periodic table. Now in HF, there is 1 Hydrogen atom and 1 Fluorine atom. Think about it: It would take 10 billion chickens laying 10 eggs per day more than 10 billion years to lay a mole of eggs. You can see the molar mass value of all the atoms from this periodic table. Now that's a big number! While a dozen eggs will make a nice omelet, a mole of eggs will fill all of the oceans on earth more than 30 million times over. (If you're confused by the form of this number refer to our The Metric System module). Just as the term dozen refers to the number twelve, the mole represents the number 6.02 x 10 23. Simply put, the mole represents a number. An updated version of this module is available.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |