The most difficult gases riddles A list of gases related questions that are most often answered incorrectly Chemistry quiz Are gas fittings tightened clockwise or anti-clockwise?It depends on the gas. 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.very hard 28% clockwiseclockwise23%anti-clockwiseanti-clockwise39%it depends on the gasit depends on the gas28%there is no standardthere is no standard8%Created by: globalquiz.org. Statistics based on 4450 answers in 4 languages »mechanics riddles » Which gas is colorless and odorless?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.hard 50% ozoneozone35%methanemethane50%benzenebenzene8%ammoniaammonia5%Created by: Kasia. Statistics based on 12258 answers in 2 languages »chemistry riddles » What is inside Swiss cheese holes?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.average 63% nitrogennitrogen8%carbon dioxidecarbon dioxide63%water vaporwater vapor3%airair24%Created by: Kasia. Statistics based on 43008 answers in 2 languages »hard simple questions riddles » Which of the following is not a chemical element?Methane. Neon, chlorine and nitrogen are chemical elements. Methane is a chemical compound, the simplest alkane and the main component of natural gas.very easy 82% neonneon11%methanemethane82%chlorinechlorine3%nitrogennitrogen2%Created by: globalquiz.org. Statistics based on 19109 answers in 2 languages »chemical elements riddles » What is the chemical symbol of helium?He. H is the chemical symbol of hydrogen. Hg is the chemical symbol of Mercury.very easy 84% HH9%HeHe84%HlHl4%HgHg1%Created by: globalquiz.org. Statistics based on 7551 answers in 2 languages »chemistry riddles » Play chemistry quiz and see all the questions.