Look around – can you imagine how many chemical reactions are happening before your eyes at this very moment? Some materials are synthesizing and some are decomposing. Some compounds are swapping molecules and some may combust. Without these reactions and our ability to predict them, there would be a smaller staff at Downton Abbey, tonic would stay fizzy, nausea would last, and the New Year would be quiet.
The most important example of synthesis occurs when hydrogen and oxygen molecules combine to make water. This is as simple and profound as creation itself. A less inspirational example of synthesis is the formation of tarnish that occurs when silver reacts with sulfur in the air to make silver sulfide. Chemists call this 2Ag + S —> Ag2S and Lord Grantham calls it a steady job.
A sad example of decomposition is the spontaneous decay of carbonic acid (H2CO3) into carbon dioxide (CO2) and water. This is why that large bottle of tonic that you have been saving for the summer G&T’s may ultimately disappoint: H2CO3 ——> CO2 + H2O.
The most interesting reactions happen when compounds swap, or replace, molecules to form new substances. Hydrochloric acid (HCl) in the stomach makes us queasy until calcium hydroxide (Ca(OH)2) arrives. Oh what a relief it is when the acid is neutralized into two products that are much easier on the stomach: calcium chloride (CaCl2) and water, 2(HCl) + Ca(OH)2 ———> CaCl2 + 2(H2O).
For sheer drama, however, no reaction can match combustion. Fireworks are made with gunpowder that produces heat and noise and metals that produce color. Copper shows blue, lithium and strontium red, and magnesium and aluminum are white when combusted. Combustion reactions produce much more energy than is required to start them and they need a lot of oxygen. Drama turns to danger when materials spontaneously combust, which happens when enough heat is generated by the reaction to ignite the materials at hand. This can happen with the right combination of microbes, moisture, heat and hay.
The laboratory of my life got a lot more reactive this week as I am making plans to use my favorite Christmas gift: a Chemistry Set with enough equipment and reagents to conduct 333 experiments. My husband (aka Santa) has offered to help me set up an area in the garage and has even volunteered to be my assistant on the condition that I call him ‘Igor’. It’s all about the chemistry.