Unizor - Physics4Teens - Energy - Atoms & Chemical Reactions
Channel: Zor Shekhtman on UNIZOR Education
Date: 2019-07-18

Unizor - Physics through a Looking Glass of Mathematician

Discussing mechanical energy, we analyzed the movement of objects.
When talking about thermal energy (heat), we had to go deeper inside the objects and analyzed the movement of molecules, the smallest parts of objects that retained the properties of objects themselves.
Now we go even deeper, inside the molecules, in search of new kinds of energy.

The components of molecules are called atoms. Currently there are more than 100 kinds of atoms, classified in the Mendeleev's Periodic Table.

Different combinations of these atoms in different quantities make up all kinds of molecules, each with its own properties.

In some cases a single atom makes up a molecule. For example, a single atom of iron (denoted by symbol Fe) makes up a molecule of iron.
In some other cases a pair of atoms of the same type makes up a molecule. For example, two atoms of oxygen (denoted by symbol O) make up a molecule of oxygen (denoted by symbol O2).
In more complicated cases a few atoms of different types make up a molecule. For example, two atoms of hydrogen (denoted by symbol H) and one atom of oxygen (O) make up a molecule of water (H2O).

One of the most complicated molecules that contains many elements in different quantities is a molecule of protein that has about half a million of atoms.

Chemical energy is a potential energy of bonds between atoms that hold them together in a molecule.
Chemical reaction is a process of re-arranging of atoms in a group of molecules, getting, as a result, a group of other molecules.
During chemical reactions some bonds between atoms are broken and some are created. Therefore, the energy might be either released or consumed in the process of chemical reaction. This energy, stored in the molecules as potential energy of atomic bonds and released or consumed during chemical reaction, is classified as chemical energy.