Carbon a streak on paper (hence its name, from the Greek verb "γράφειν" which means "to write"), while diamond is the hardest naturally occurring material known. Graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials. All carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form at standard temperature and pressure. They are chemically resistant and require high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is
History of the petroleum industry in Canada (oil sands and heavy oil) gas - has four hydrogen atoms for every carbon atom. It has light gravity, and takes the form of a gas at normal temperatures and pressures. The next heavier hydrocarbon, ethane, has the chemical formula CH and is a slightly denser gas. Gases, of course, have no gravity at atmospheric temperatures and pressures. Organic compounds combining carbon and oxygen are many in number. Those with more carbon atoms per hydrogen atom are heavier and denser. Most hydrocarbons are liquid under standard conditions, with greater viscosity associated with greater gravity. Heavy oil and bitumen, which have far more carbon mass than