A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
To the uninitiated, a chemical reaction must seem like an act of magic.
A chemist puts one or two reagents into a flask, warms them for a period of time, and then takes from the flask one or more
completely different compounds. It is, until we understand the details of the reaction, like a magician who puts apples and oranges in a hat,
shakes it, and then pulls out rabbits and parrots.
Now we'll try to understand how this chemical magic takes place.
We need to be able to explain how the products of the reaction are formed.
This explanation will take the form of a mechanism for the reaction–a description of
the events that take place on a molecular level as reactants become products.
Often the reaction takes place in more than one step.
We will know what chemical species, called intermediates, intervene between each step along the way.