What is the difference between chemical reactions and chemical equations?
Chemical reactions are what actually occurs in a test-tube, a flask, or in a reactor; chemical equations are our attempts to rationalize and quantify this reactivity.
At present, in Old Blighty, my room is heated by a chemical reaction; that is by the combustion of natural gas to give carbon dioxide and water. My motor is also driven by the combustion of diesel, another chemical reaction.
I can write equations that represent this reactivity:
Both chemical equations are idealized. Certainly, for the diesel combustion, there is going to be a significant degree of incomplete combustion to give