# How does a chemical reaction work?

Sep 28, 2016

The elements and compounds recombine in new state that is more stable than the previous combinations.

#### Explanation:

All equations of chemical reactions result in an increase in Gibb's free energy equation.

Most chemical reactions result in a release of heat energy which results in a more stable energy configuration, (exothermic)

Fewer chemical reactions are endothermic. If these reactions are "spontaneous" it is because the reactions have resulted in a large increase in entropy ( disorder) which over comes the increase in heat energy. The law of entropy is universal and results in a more stable disordered state.

At a simpler level a when the elements combine they create a more stable electron configuration, usually the configuration of group VIIIA. ( the inert, or noble gases) e

A classic example is $2 N {a}_{s} + 1 C {l}_{2} \left(g\right) = = 2 N {a}^{+} C {l}^{-} 1$

Both atoms have a much more stable state when combined than before they combine. Sodium (Na) has lost one electron to achieve the electron configuration of $N {e}_{10}$ which is stable. While Chlorine (Cl) has gained one electron to achieve the electron configuration of $A {r}_{18}$ which is stable.

All spontaneous chemical reactions work by achieving more stable
structures and configurations.

Oct 17, 2016

In a chemical reaction, some bonds are broken and the particles rearrange to form new bonds and make new substances.

#### Explanation:

An example is the reaction between sodium metal and chlorine gas to form sodium chloride.

$\text{2Na(s)" + "Cl"_2"(g)" → "2NaCl(s)}$

The sodium atoms are bound to other sodium atoms in the metal by metallic bonds. They must break free of these bonds to react with the chlorine.

Similarly, the chlorine atoms are bound to each other by covalent bonds. They must break free of these bonds to react with the sodium.

Then the sodium atoms and the chlorine can make new bonds to each other and form sodium chloride.

We can view the reaction as if it took place in three steps:

"2Na(in metal)" → color(red)(cancel(color(black)("2Na")))
"Cl"_2"(g)" → color(red)(cancel(color(black)("2Cl")))
color(red)(cancel(color(black)("2Na"))) + color(red)(cancel(color(black)("2Cl"))) → "2NaCl(s)"