Chapter 1 · The Chemical World
1.2Chemicals Compose Ordinary Things
8 min · two checks
Predict
Can a product be chemical-free?
The idea
- Give the main chemicals in air, table salt, and a cotton fiber.
- Separate “natural versus synthetic” from “safe versus harmful.”
Dry air is about 78% nitrogen, N₂, 21% oxygen, O₂, about 1% argon, and a smaller share of carbon dioxide and other gases. Table salt is sodium chloride, NaCl. A cotton shirt is mostly cellulose, a long chain built from glucose units. The apple on the counter is water, sugars, acids, fiber, and pigments. Ordinary life is already a catalog of substances.
Origin is not the same thing as hazard. Water distilled in a lab and water condensed from a cloud are the same substance, H₂O. Vitamin C from an orange and vitamin C made in a factory are the same molecule. Some natural compounds are potent poisons; some synthetic ones are medicines. Judge a substance by its identity, dose, and use — not by whether a factory or a plant made it.
Keep these
- Everything with mass is chemical, including food, air, and fabric.
- Natural and synthetic describe origin, not automatically safety.
- The same molecule has the same properties no matter who produced it.