20 Chemistry Facts
1. Water is the only naturally occurring substance on Earth that exists as a solid, liquid, and gas within the normal range of temperatures.
2. The periodic table currently contains 118 confirmed elements, with the heaviest ones created artificially in laboratories.
3. Gold is so chemically unreactive that it never tarnishes or rusts, which is why ancient gold artifacts still shine today.
4. Oxygen makes up about 65% of the human body's mass and 21% of Earth's atmosphere by volume.
5. Diamond and graphite are both made entirely of carbon atoms — but their vastly different structures produce completely different properties.
6. Helium was first discovered on the Sun through spectroscopy before it was ever found on Earth — its name comes from Helios, the Greek sun god.
7. A single teaspoon of neutron star material would weigh billions of tonnes because it consists of densely packed nuclear matter.
8. Dry ice is solid carbon dioxide that sublimates directly from solid to gas at room temperature, skipping the liquid phase entirely.
9. Chlorine added to drinking water in very small amounts kills harmful microorganisms and has saved millions of lives over the past century.
10. Silicon is the second most abundant element in Earth's crust and forms the basis of both glass and modern computer chips.
11. Hydrogen is the most abundant element in the universe, making up about 75% of all normal matter by mass.
12. Liquid nitrogen boils at –196°C and is used in medicine, food preservation, and scientific research around the world.
13. The pH scale measures acidity and alkalinity — a pH of 7 is neutral, below 7 is acidic, and above 7 is alkaline.
14. Rust is the result of iron reacting with oxygen and water in a process called oxidation, which weakens metals over time.
15. Baking soda and vinegar react to produce carbon dioxide gas, water, and sodium acetate in a classic acid-base reaction.
16. Neon signs glow because electricity excites neon gas atoms, which then emit photons of light as the electrons return to lower energy states.
17. Mercury is the only metal that is liquid at room temperature, with a melting point of –39°C.
18. The smell of rain on dry earth is called petrichor, caused by chemical compounds released from soil and plants when water hits them.
19. Ozone (O₃) is a molecule made of three oxygen atoms that forms a protective layer in the stratosphere, absorbing harmful UV radiation.
20. Phosphorus is so reactive that white phosphorus ignites spontaneously in air and must be stored underwater to prevent combustion.