Chemical formula and Related Topics

Chemical compound

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Chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds.

A chemical formula specifies the number of atoms of each element in a compound molecule, using the standard abbreviations for the chemical elements and numerical subscripts.

Joseph Priestley is usually given priority in the discovery.

Oxygen

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Chemical element with the symbol O and atomic number 8.

Antoine Lavoisier discredited the phlogiston theory.

Robert H. Goddard and a liquid oxygen-gasoline rocket

An experiment setup for preparation of oxygen in academic laboratories

Orbital diagram, after Barrett (2002), showing the participating atomic orbitals from each oxygen atom, the molecular orbitals that result from their overlap, and the aufbau filling of the orbitals with the 12 electrons, 6 from each O atom, beginning from the lowest-energy orbitals, and resulting in covalent double-bond character from filled orbitals (and cancellation of the contributions of the pairs of σ and σ* and π and π* orbital pairs).

Liquid oxygen, temporarily suspended in a magnet owing to its paramagnetism

Space-filling model representation of dioxygen (O2) molecule

Late in a massive star's life, 16O concentrates in the O-shell, 17O in the H-shell and 18O in the He-shell.

500 million years of climate change vs. 18O

Photosynthesis splits water to liberate and fixes into sugar in what is called a Calvin cycle.

build-up in Earth's atmosphere: 1) no produced; 2) produced, but absorbed in oceans & seabed rock; 3) starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4–5) sinks filled and the gas accumulates

Hofmann electrolysis apparatus used in electrolysis of water.

Oxygen and MAPP gas compressed-gas cylinders with regulators

An oxygen concentrator in an emphysema patient's house

Low pressure pure is used in space suits.

Most commercially produced is used to smelt and/or decarburize iron.

Water is the most familiar oxygen compound.

Oxides, such as iron oxide or rust, form when oxygen combines with other elements.

The interior of the Apollo 1 Command Module. Pure at higher than normal pressure and a spark led to a fire and the loss of the Apollo 1 crew.

At standard temperature and pressure, oxygen is a colorless, odorless, and tasteless gas with the molecular formula, referred to as dioxygen.

Hydrogen

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Chemical element with the symbol H and atomic number 1.

Depiction of a hydrogen atom with size of central proton shown, and the atomic diameter shown as about twice the Bohr model radius (image not to scale)

Hydrogen gas is colorless and transparent, here contained in a glass ampoule.

Phase diagram of hydrogen. The temperature and pressure scales are logarithmic, so one unit corresponds to a 10x change. The left edge corresponds to 105 Pa, which is about atmospheric pressure.

Hydrogen emission spectrum lines in the visible range. These are the four visible lines of the Balmer series

NGC 604, a giant region of ionized hydrogen in the Triangulum Galaxy

At standard conditions hydrogen is a gas of diatomic molecules having the formula H2.

A thermite reaction using iron(III) oxide. The sparks flying outwards are globules of molten iron trailing smoke in their wake.

Chemical reaction

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Process that leads to the chemical transformation of one set of chemical substances to another.

Antoine Lavoisier developed the theory of combustion as a chemical reaction with oxygen.

As seen from the equation CH4 + 2O2 -> CO2 + 2 H2O, a coefficient of 2 must be placed before the oxygen gas on the reactants side and before the water on the products side in order for, as per the law of conservation of mass, the quantity of each element does not change during the reaction

An example of organic reaction: oxidation of ketones to esters with a peroxycarboxylic acid

Isomerization of azobenzene, induced by light (hν) or heat (Δ)

Representation of four basic chemical reactions types: synthesis, decomposition, single replacement and double replacement.

Sodium chloride is formed through the redox reaction of sodium metal and chlorine gas

Ferrocene – an iron atom sandwiched between two C5H5 ligands

In this Paterno–Büchi reaction, a photoexcited carbonyl group is added to an unexcited olefin, yielding an oxetane.

Schematic potential energy diagram showing the effect of a catalyst in an endothermic chemical reaction. The presence of a catalyst opens a different reaction pathway (in red) with a lower activation energy. The final result and the overall thermodynamics are the same.

Solid heterogeneous catalysts are plated on meshes in ceramic catalytic converters in order to maximize their surface area. This exhaust converter is from a Peugeot 106 S2 1100

Mechanism of electrophilic aromatic substitution

Electrophilic addition of hydrogen bromide

Acid-catalyzed addition-elimination mechanism

The Cope rearrangement of 3-methyl-1,5-hexadiene

Illustration of the induced fit model of enzyme activity

Thermite reaction proceeding in railway welding. Shortly after this, the liquid iron flows into the mould around the rail gap.

They consist of chemical or structural formulas of the reactants on the left and those of the products on the right.

Ethanol

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Organic chemical compound.

Ethanol burning with its spectrum depicted

Hydrogen bonding in solid ethanol at −186 °C

94% denatured ethanol sold in a bottle for household use

Infrared reflection spectra of liquid ethanol, showing the −OH band centered near 3300 cm−1 and C−H bands near 2950 cm−1

Near-infrared spectrum of liquid ethanol

It is a simple alcohol with the chemical formula C2H6O.

Molecule

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Group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion.

A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings.

AFM image of 1,5,9-trioxo-13-azatriangulene and its chemical structure.

A covalent bond forming H2 (right) where two hydrogen atoms share the two electrons

Sodium and fluorine undergoing a redox reaction to form sodium fluoride. Sodium loses its outer electron to give it a stable electron configuration, and this electron enters the fluorine atom exothermically.

3D (left and center) and 2D (right) representations of the terpenoid molecule atisane

Structure and STM image of a "cyanostar" dendrimer molecule.

Hydrogen can be removed from individual H2TPP molecules by applying excess voltage to the tip of a scanning tunneling microscope (STM, a); this removal alters the current-voltage (I-V) curves of TPP molecules, measured using the same STM tip, from diode like (red curve in b) to resistor like (green curve). Image (c) shows a row of TPP, H2TPP and TPP molecules. While scanning image (d), excess voltage was applied to H2TPP at the black dot, which instantly removed hydrogen, as shown in the bottom part of (d) and in the rescan image (e). Such manipulations can be used in single-molecule electronics.

The chemical formula for a molecule uses one line of chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, and plus (+) and minus (−) signs.

Glucose

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Glucose can exist in both a straight-chain and ring form.

Widely proposed arrow-pushing mechanism for acid-catalyzed dynamic equilibrium between the α- and β- anomers of D-glucopyranose

Glucose metabolism and various forms of it in the process.Glucose-containing compounds and isomeric forms are digested and taken up by the body in the intestines, including starch, glycogen, disaccharides and monosaccharides.Glucose is stored in mainly the liver and muscles as glycogen. It is distributed and used in tissues as free glucose.

Diagram showing the possible intermediates in glucose degradation; Metabolic pathways orange: glycolysis, green: Entner-Doudoroff pathway, phosphorylating, yellow: Entner-Doudoroff pathway, non-phosphorylating

Relative sweetness of various sugars in comparison with sucrose

Glucose is a simple sugar with the molecular formula C6H12O6.

The Cativa process converts methanol into acetic acid.

Methanol, also known as methyl alcohol, amongst other names, is an organic chemical and the simplest alcohol, with the formula CH3OH (a methyl group linked to a hydroxyl group, often abbreviated MeOH).

Isomer

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Structural isomers of : I 1-propanol, II 2-propanol, III ethyl-methyl-ether.

Molecular models of cyclohexane in boat and chair conformations. The carbon atoms are colored amber or blue according to whether they lie above or below the mean plane of the ring. The C–C bonds on the ring are light green.

The two isomeric complexes, cisplatin and transplatin, are examples of square planar MX2Y2 molecules with M = Pt.

In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space.