Whilst alchemy symbols has mainly been used to represent elements a number of them were used to represent compounds and even techniques. Whilst alchemists at the time did not know them as compounds they knew they were different to common elements that had been discovered. Nitric acid for example discovered by Islamic alchemists was known as aqua fortis and was named as it was a liquid much like water but had different properties. Whilst ethanol was known as spirit of wine or aqua vitae. Alchemical processes were associated with the signs of the zodiac and used to represent different methods alchemists took when discovering or working with different elements. For example, distillation was associated with the symbol for Virgo and separation with the symbol for Libra.
Ethanol is a compound of hydrogen, carbon and oxygen and is used in alcoholic drinks and as a fuel due to it being easy to burn.
The signs of the zodiac are the star signs made by the stars in the sky that according to astrology are related to a persons birth and their personality
Distillation is a separation technique that can be used to separate out liquids from each other by their boiling points.
Separation is a term to describe the distance between particles