A report on Chemical reaction

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

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.

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

- Chemical reaction

74 related topics with Alpha

An oil painting of a chemist (Ana Kansky, painted by Henrika Šantel in 1932)

Chemistry

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Scientific study of the properties and behavior of matter.

Laboratory, Institute of Biochemistry, University of Cologne in Germany.

Solutions of substances in reagent bottles, including ammonium hydroxide and nitric acid, illuminated in different colors

A diagram of an atom based on the Bohr model

Standard form of the periodic table of chemical elements. The colors represent different categories of elements

Carbon dioxide (CO2), an example of a chemical compound

A ball-and-stick representation of the caffeine molecule (C8H10N4O2).

A 2-D structural formula of a benzene molecule (C6H6)

Diagram showing relationships among the phases and the terms used to describe phase changes.

An animation of the process of ionic bonding between sodium (Na) and chlorine (Cl) to form sodium chloride, or common table salt. Ionic bonding involves one atom taking valence electrons from another (as opposed to sharing, which occurs in covalent bonding)

In the methane molecule (CH4), the carbon atom shares a pair of valence electrons with each of the four hydrogen atoms. Thus, the octet rule is satisfied for C-atom (it has eight electrons in its valence shell) and the duet rule is satisfied for the H-atoms (they have two electrons in their valence shells).

During chemical reactions, bonds between atoms break and form, resulting in different substances with different properties. In a blast furnace, iron oxide, a compound, reacts with carbon monoxide to form iron, one of the chemical elements, and carbon dioxide.

The crystal lattice structure of potassium chloride (KCl), a salt which is formed due to the attraction of K+ cations and Cl− anions. Note how the overall charge of the ionic compound is zero.

Hydrogen bromide exists in the gas phase as a diatomic molecule

Democritus' atomist philosophy was later adopted by Epicurus (341–270 BCE).

15th-century artistic impression of Jābir ibn Hayyān (Geber), a Perso-Arab alchemist and pioneer in organic chemistry.

Antoine-Laurent de Lavoisier is considered the "Father of Modern Chemistry".

In his periodic table, Dmitri Mendeleev predicted the existence of 7 new elements, and placed all 60 elements known at the time in their correct places.

Top: Expected results: alpha particles passing through the plum pudding model of the atom undisturbed.
Bottom: Observed results: a small portion of the particles were deflected, indicating a small, concentrated charge.

It is a natural science that covers the elements that make up matter to the compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.

Enzyme

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Enzymes are proteins that act as biological catalysts (biocatalysts).

Enzyme activity initially increases with temperature (Q10 coefficient) until the enzyme's structure unfolds (denaturation), leading to an optimal rate of reaction at an intermediate temperature.

Organisation of enzyme structure and lysozyme example. Binding sites in blue, catalytic site in red and peptidoglycan substrate in black.

Enzyme changes shape by induced fit upon substrate binding to form enzyme-substrate complex. Hexokinase has a large induced fit motion that closes over the substrates adenosine triphosphate and xylose. Binding sites in blue, substrates in black and Mg2+ cofactor in yellow.

Chemical structure for thiamine pyrophosphate and protein structure of transketolase. Thiamine pyrophosphate cofactor in yellow and xylulose 5-phosphate substrate in black.

The energies of the stages of a chemical reaction. Uncatalysed (dashed line), substrates need a lot of activation energy to reach a transition state, which then decays into lower-energy products. When enzyme catalysed (solid line), the enzyme binds the substrates (ES), then stabilizes the transition state (ES‡) to reduce the activation energy required to produce products (EP) which are finally released.

The metabolic pathway of glycolysis releases energy by converting glucose to pyruvate via a series of intermediate metabolites. Each chemical modification (red box) is performed by a different enzyme.

In phenylalanine hydroxylase over 300 different mutations throughout the structure cause phenylketonuria. Phenylalanine substrate and tetrahydrobiopterin coenzyme in black, and Fe2+ cofactor in yellow.

Hereditary defects in enzymes are generally inherited in an autosomal fashion because there are more non-X chromosomes than X-chromosomes, and a recessive fashion because the enzymes from the unaffected genes are generally sufficient to prevent symptoms in carriers.

Catalysts accelerate chemical reactions.

A range of industrial catalysts in pellet form

Catalysis

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An air filter that utilizes a low-temperature oxidation catalyst to convert carbon monoxide to less toxic carbon dioxide at room temperature. It can also remove formaldehyde from the air.

Generic potential energy diagram showing the effect of a catalyst in a hypothetical exothermic chemical reaction X + Y to give Z. The presence of the catalyst opens a different reaction pathway (shown in red) with a lower activation energy. The final result and the overall thermodynamics are the same.

The microporous molecular structure of the zeolite ZSM-5 is exploited in catalysts used in refineries

Zeolites are extruded as pellets for easy handling in catalytic reactors.

Left: Partially caramelized cube sugar, Right: burning cube sugar with ash as catalyst

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst.

Sodium and fluorine bonding ionically to form sodium fluoride. Sodium loses its outer electron to give it a stable electron configuration, and this electron enters the fluorine atom exothermically. The oppositely charged ions are then attracted to each other. The sodium is oxidized; and the fluorine is reduced.

Redox

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The international pictogram for oxidizing chemicals

A redox reaction is the force behind an electrochemical cell like the Galvanic cell pictured. The battery is made out of a zinc electrode in a ZnSO4 solution connected with a wire and a porous disk to a copper electrode in a CuSO4 solution.

Oxides, such as iron(III) oxide or rust, which consists of hydrated iron(III) oxides Fe2O3·nH2O and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3), form when oxygen combines with other elements

Enzymatic browning is an example of a redox reaction that takes place in most fruits and vegetables.

Blast furnaces of Třinec Iron and Steel Works, Czech Republic

Redox (reduction–oxidation,, ) is a type of chemical reaction in which the oxidation states of substrate change.

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.

It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds.

Chemical element

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Species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species.

$Estimated distribution of dark matter and dark energy in the universe. Only the fraction of the mass and energy in the universe labeled "atoms" is composed of chemical elements.$

Periodic table showing the cosmogenic origin of each element in the Big Bang, or in large or small stars. Small stars can produce certain elements up to sulfur, by the alpha process. Supernovae are needed to produce "heavy" elements (those beyond iron and nickel) rapidly by neutron buildup, in the r-process. Certain large stars slowly produce other elements heavier than iron, in the s-process; these may then be blown into space in the off-gassing of planetary nebulae

Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, from the Big Bang. The next three elements (Li, Be, B) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar-produced elements are: (1) an alternation of abundance in elements as they have even or odd atomic numbers (the Oddo-Harkins rule), and (2) a general decrease in abundance as elements become heavier. Iron is especially common because it represents the minimum energy nuclide that can be made by fusion of helium in supernovae.

Mendeleev's 1869 periodic table: An experiment on a system of elements. Based on their atomic weights and chemical similarities.

When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds.

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

In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "inflammable air".

Conversion of the disaccharide sugar lactose (substrate) to two monosaccharide sugars (products) by lactase (enzyme)

Product (chemistry)

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Products are the species formed from chemical reactions.

Steam and liquid water are two different forms of the same chemical (pure) substance: water.

Chemical substance

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Form of matter having constant chemical composition and characteristic properties.

Colors of a single chemical (Nile red) in different solvents, under visible and UV light, showing how the chemical interacts dynamically with its solvent environment.

Native sulfur crystals. Sulfur occurs naturally as elemental sulfur, in sulfide and sulfate minerals and in hydrogen sulfide.

Potassium ferricyanide is a compound of potassium, iron, carbon and nitrogen; although it contains cyanide anions, it does not release them and is nontoxic.

Cranberry glass, while appearing homogeneous, is a mixture consisting of glass and gold colloidal particles of about 40nm in diameter, giving it a red color.

Chemicals in graduated cylinders and beaker.

Chemical substances may be combined or converted to others by means of chemical reactions.

Reaction rate

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Wood combustion has a high reaction rate. This process is fast.

The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time.