The most difficult gases riddles

Some gas fittings use reverse threads to prevent disastrous misconnections. For example, oxygen fittings are right-handed, but acetylene and other flammable gases use left-handed fittings.

Jan Baptist van Helmont (1580–1644) was a Flemish chemist, physiologist, and physician. He worked during the years just after Paracelsus and the rise of iatrochemistry, and is sometimes considered to be "the founder of pneumatic chemistry". Van Helmont is remembered today largely for his ideas on spontaneous generation, his 5-year tree experiment, and his introduction of the word "gas" (from the Greek word chaos) into the vocabulary of science.

Methane is the main component of natural gas piped into homes for domestic heating and cooking purposes. In order to assist in detecting leaks, a sulphur-like odorant is added the gas used by consumers.

Carbon dioxide is produced by bacteria feeding on the lactic acid. In the Middle Ages, the holes were considered a sign of imperfection and cheese makers would try to avoid them.

By far most of the solar system's mass is in the Sun itself: somewhere between 99.8 and 99.9 percent. The rest is split between the planets and their satellites, and the comets and asteroids and the dust and gas surrounding our star.

Neon, chlorine and nitrogen are chemical elements. Methane is a chemical compound, the simplest alkane and the main component of natural gas.

H is the chemical symbol of hydrogen. Hg is the chemical symbol of Mercury.