Chemie
20 cards from across every topic, each citing a source. Tap one to open it in the feed.
- A litre of osmium weighs 22.6 kilograms.
Osmium is the densest stable element: 22.587 grams per cubic centimetre, twice as dense as lead. Iridium trails by a …
- Bread crust, steak and coffee owe their flavour to the same reaction.
From roughly 140 to 165 °C, amino acids react with sugars into hundreds of new flavour and colour compounds: the …
- Diamond and pencil lead are made of exactly the same stuff.
Both are pure carbon. In diamond, every atom bonds tightly to four neighbours in a three-dimensional lattice, hence the …
- Disturb a system at equilibrium and it pushes back.
Henry Le Chatelier stated in 1884: change the pressure, temperature or concentration of an equilibrium and it shifts so …
- Every party balloon loses helium to space for good.
Helium is so light that it escapes from the atmosphere into space. Only 5.2 parts per million of air are helium. Fresh …
- Everything is poison. Only the amount matters.
The physician Paracelsus wrote in 1538: all things are poison, and the dose alone makes a thing not a poison. Too much …
- Half the nitrogen in your body came out of a factory.
Since 1913 the Haber-Bosch process has squeezed nitrogen from air at 250 to 350 bar and around 500 °C into ammonia, the …
- How a leaf builds sugar out of air and light.
Chlorophyll captures light and uses it to split water, releasing the oxygen you breathe. The captured energy squeezes …
- How baking powder puffs up a cake, and why baking soda alone can't.
Baking powder is sodium bicarbonate plus a dry acid plus a little starch against moisture. As soon as liquid joins …
- How your phone battery stores power: as migrating ions.
A lithium-ion battery has two electrodes, graphite and a metal oxide, separated by an electrolyte. While charging …
- On Everest, water boils at about 70 degrees.
Water boils when its vapour pressure matches the air pressure. At sea level that happens at 100 °C. The higher you …
- Properly stored honey keeps indefinitely.
Honey holds only about 18 percent water; the rest is sugar that pulls water out of any microbe. Add a pH of around 3.9 …
- Soap cleans because its molecules have two faces.
A soap molecule has a water-loving head and a long fat-loving tail. In water, the tails burrow into grease droplets …
- Stainless steel doesn't rust because it heals itself.
Steel counts as stainless once it contains at least 10.5 percent chromium. The chromium reacts with oxygen in the air …
- The gold in your ring was forged when dead stars collided.
Stars fuse elements in their cores only up to iron. Heavier ones like gold, platinum and uranium need extreme floods of …
- The onion isn't crying. It's shooting.
An intact onion doesn't sting. Only your knife breaks cell walls, letting two separately stored substances meet: an …
- The strongest known material was discovered with sticky tape.
Graphene is a single layer of carbon atoms in a honeycomb lattice, just one atom thick. In 2004, Andre Geim and …
- Water is heaviest at 4 degrees. That saves fish.
Almost every substance gets denser as it cools. Water only does so down to 4 °C. Below that, hydrogen bonds arrange the …
- Why road salt melts ice while staying ice cold.
Dissolved particles disrupt the ice crystal lattice, so salt water freezes below 0 °C. Salt on ice dissolves into the …
- You taste fizz with your 'sour' cells, not with the bubbles.
On the sour-sensing cells of your tongue sits an enzyme, carbonic anhydrase 4. It turns dissolved CO2 into carbonic …