periodic table periodic table with molar mass

#PERIODIC TABLE PERIODIC TABLE WITH MOLAR MASS FULL#

The detection of a burning hydrogen leak may require a flame detector such leaks can be very dangerous. Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to the naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine, compared to the highly visible plume of a Space Shuttle Solid Rocket Booster, which uses an ammonium perchlorate composite. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 ☌ (932 ☏). Hydrogen gas forms explosive mixtures with air in concentrations from 4–74% and with chlorine at 5–95%. The enthalpy of combustion is −286 kJ/mol. Hydrogen gas ( dihydrogen or molecular hydrogen) is highly flammable:Ģ H 2(g) + O 2(g) → 2 H 2O(l) (572 kJ/2 mol = 286 kJ/mol = 141.865 MJ/kg)

#PERIODIC TABLE PERIODIC TABLE WITH MOLAR MASS FULL#

The Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust. When the bottom cap is removed, allowing air to enter at the bottom, the hydrogen in the container rises out of top and burns as it mixes with the air. Properties Combustion Combustion of hydrogen with the oxygen in the air. Combustion of hydrogen can lead to the thermal formation of nitrogen oxides.

When hydrogen is consumed in fuel cells, the only emission at the point of use is water vapour. Hydrogen can be deployed as an energy source in fuel cells to produce electricity, or via combustion to generate heat. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production. A small percentage is also produced using more energy-intensive methods such as the electrolysis of water. Industrial production is mainly from steam reforming of natural gas. In 1766–1781, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance and that it produces water when burned, the property for which it was later named: in Greek, hydrogen means 'water-former'. Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Because hydrogen is the only neutral atom for which the Schrödinger equation can be solved analytically, the study of its energetics and chemical bonding has played a key role in the development of quantum mechanics. The H + cation is simply a proton (symbol p) but its behavior in aqueous solutions and in ionic compounds involves screening of its electric charge by nearby polar molecules or anions. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) where it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H +. Hydrogen plays a particularly important role in acid–base reactions because these reactions usually involve the exchange of protons between soluble molecules. Hydrogen is nonmetallic (except when it becomes metallic at extremely high pressures) and readily forms a single covalent bond with most nonmetallic elements, forming compounds such as water and nearly all organic compounds. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 years later during the recombination epoch, when the plasma had cooled enough for electrons to remain bound to protons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds.

Stars such as the Sun are mainly composed of hydrogen in the plasma state. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter. It is colorless, odorless, tasteless, non-toxic, and highly combustible. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H 2. Hydrogen is a chemical element it has symbol H and atomic number 1.

Periodic table periodic table with molar mass