H2O is water. C (sea) H2O is seawater.

C6H8O7 is the organic compound citric acid, which is found in many citrus fruits (in this case, lemons). There is a popular adage that if life gives one lemons, it is best to make lemonade. In this joke, when life gives you C6H8O7 (citric acid/lemon juice), add H2O (water) and C12H22O11 (and table sugar/sucrose) to make lemonade.

In chemistry, a Florence Flask is a type of laboratory glassware with a round body and long neck. An Erlenmeyer flask (conical flask) is a type of laboratory glassware that is flat-bottomed and has a narrow neck. A joule (J) is a unit of energy which denotes the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one meter. A solution is a homogenous mixture of two or more substances. For this joke, a woman (Florence Flask) thinks she loses her jewels (joules) before the opera and asks her husband (Erlenmeyer Flask) to help her. He comforts her by trying to find the solution to her problem.

The noble class refers to the aristocracy or ruling class. A king would be a part of the noble class. In chemistry, noble gases refer to 7 elements which are unlikely to bond with other elements (helium, neon, argon, krypton, xenon, radon, and ununoctium).

Chromatography is a technique used to separate mixtures. They have a stationary phase (solid or liquid supported on a solid) and a mobile phase (liquid or gas). Some people believe that humans go through phases regarding the things they like.

CSI (Crime Scene Investigation) is a popular television show. CSI also refers to the periodic symbols for cesium and iodine: Cs and I.

Organic chemistry is a sub-discipline of chemistry and is extremely difficult to understand. It can take years, even decades to fully understand its complexities.

This is a picture of Amedeo Avogrado, the scientist who came up with the formula for one mole of any substance: 6.02214179(30)x10²³.

Chemistry is a science in which chemists work with many dangerous substances. Ingestion can cause serious illness or possibly death! Do not lick the spoon!

While CoFe2 looks like “coffee”, this joke refers to a chemical compound: one cobalt (Co) atom and two iron (Fe) atoms.