Search results
Results from the WOW.Com Content Network
Hydrazine is an inorganic compound with the chemical formula N 2 H 4.It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour.Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate (N 2 H 4 ·xH 2 O).
1625 – First description of hydrogen by Johann Baptista van Helmont. First to use the word "gas". 1650 – Turquet de Mayerne obtains a gas or "inflammable air" by the action of dilute sulphuric acid on iron. 1662 – Boyle's law (gas law relating pressure and volume). 1670 – Robert Boyle produces hydrogen by reacting metals with acid.
Deuterium, 2 H (atomic mass 2.014 101 777 844 (15) Da), the other stable hydrogen isotope, has one proton and one neutron in its nucleus, called a deuteron. 2 H comprises 26–184 ppm (by population, not mass) of hydrogen on Earth; the lower number tends to be found in hydrogen gas and higher enrichment (150 ppm) is typical of seawater.
Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H 2, sometimes called dihydrogen, [11] hydrogen gas, molecular hydrogen, or simply hydrogen. It is colorless, odorless, [12] non-toxic, and highly combustible.
Instead, many compounds have hydrogen centres with hydridic character. Aside from electride, the hydride ion is the simplest possible anion, consisting of two electrons and a proton. Hydrogen has a relatively low electron affinity, 72.77 kJ/mol and reacts exothermically with protons as a powerful Lewis base.
For instance, carbon and hydrogen will not directly react to form methane (CH 4), so that the standard enthalpy of formation cannot be measured directly. However the standard enthalpy of combustion is readily measurable using bomb calorimetry. The standard enthalpy of formation is then determined using Hess's law. The combustion of methane:
A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe. [1]
Deuterium (hydrogen-2, symbol 2 H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen; the other is protium, or hydrogen-1, 1 H. The deuterium nucleus ( deuteron ) contains one proton and one neutron , whereas the far more common 1 H has no neutrons.