query: has_part pimaric acid
supports: Tin is a chemical element with the symbol Sn (for ) and atomic number 50, is a post-transition metal in group 14 of the periodic table. It is obtained chiefly from the mineral cassiterite, which contains tin dioxide, SnO. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table, thanks to its magic number of protons. It has two main allotropes: at room temperature, the stable allotrope is -tin, a silvery-white, malleable metal, but at low temperatures it transforms into the less dense grey -tin, which has the diamond cubic structure. Metallic tin is not easily oxidized in air. A carboxylic acid is an organic compound that contains a carboxyl group (C(=O)OH). The general formula of a carboxylic acid is RCOOH, with R referring to the rest of the (possibly quite large) molecule. Carboxylic acids occur widely and include the amino acids (which make up proteins) and acetic acid (which is part of vinegar and occurs in metabolism). Oleoresins are semi-solid extracts composed of a resin in solution in an essential and/or fatty oil, obtained by evaporation of the solvent(s) used for their production. Naturally occurring oleoresins are also known as balsams. In chemistry isomerization (also isomerisation) is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms have a different arrangement e.g. A-B-C  B-A-C (these related molecules are known as isomers ). In some molecules and under some conditions, isomerization occurs spontaneously. Many isomers are equal or roughly equal in bond energy, and so exist in roughly equal amounts, provided that they can interconvert somewhat freely; that is, the energy barrier between the two isomers is not too high. When the isomerization occurs intramolecularly it is considered a rearrangement reaction. Rosin, also called colophony or Greek pitch, is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature rosin is brittle, but it melts at stove-top temperature. It chiefly consists of various resin acids, especially abietic acid. The term "colophony" comes from ', Latin for "resin from Colophon," an ancient Ionic city. Tempera, also known as egg tempera, is a permanent, fast-drying painting medium consisting of colored pigments mixed with a water-soluble binder medium (usually a glutinous material such as egg yolk or some other size). Tempera also refers to the paintings done in this medium. Tempera paintings are very long lasting, and examples from the 1st centuries AD still exist. Egg tempera was a primary method of painting until after 1500 when it was superseded by the invention of oil painting. A paint consisting of pigment and glue size commonly used in the United States as poster paint is also often referred to as "tempera paint," although the binders and sizes in this paint are different from traditional tempera paint. Acetic acid , systematically named ethanoic acid , is a colourless liquid organic compound with the chemical formula CHCOOH (also written as CHCOH or CHO). When undiluted, it is sometimes called "glacial acetic acid". Vinegar is roughly 39% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Acetic acid has a distinctive sour taste and pungent smell. In addition to household vinegar, it is mainly produced as a precursor to polyvinyl acetate and cellulose acetate. Although it is classified as a weak acid, concentrated acetic acid is corrosive and can attack the skin. Vinegar is a liquid consisting of about 520% acetic acid (CHCOOH), water, and other trace chemicals, which may include flavorings. The acetic acid is produced by the fermentation of ethanol by acetic acid bacteria. Vinegar is now mainly used as a cooking ingredient, or in pickling. As the most easily manufactured mild acid, it has historically had a great variety of industrial, medical, and domestic uses, some of which (such as its use as a general household cleaner) are still commonly practiced today. An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group COOH. Sulfonic acids, containing the group SOOH, are relatively stronger acids. Alcohols, with OH, can act as acids but they are usually very weak. The relative stability of the conjugate base of the acid determines its acidity. Other groups can also confer acidity, usually weakly: the thiol group SH, the enol group, and the phenol group. In biological systems, organic compounds containing these groups are generally referred to as organic acids. A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge. However, in quantum physics, organic chemistry, and biochemistry, the term "molecule" is often used less strictly, also being applied to polyatomic ions. In polymer chemistry and materials science, resin is a "solid or highly viscous substance" of plant or synthetic origin that is typically convertible into polymers. They are often mixtures of organic compounds, principally terpenes. Many plants, particularly woody plants, produce resin in response to injury. The resin acts as a bandage protecting the plant from invading insects and pathogens. Resin acid refers to mixtures of several related carboxylic acids, primarily abietic acid, found in tree resins. Nearly all resin acids have the same basic skeleton: three fused ring fused with the empirical formula CHCOOH. Resin acids are tacky, yellowish gums that are water-insoluble. They are used to produce soaps for diverse applications, but their use is being displaced increasingly by synthetic acids such as 2-ethylhexanoic acid or petroleum-derived naphthenic acids. 2-Ethylhexanoic acid is the organic compound with the formula CH(CH)CH(CH)COH. It is a carboxylic acid that is widely used to prepare lipophilic metal derivatives that are soluble in nonpolar organic solvents. 2-Ethylhexanoic acid is a colorless viscous oil. It is supplied as a racemic mixture. An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of central importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry. In chemistry, esters are chemical compounds derived from an acid (organic or inorganic) in which at least one OH (hydroxyl) group is replaced by an Oalkyl (alkoxy) group. Usually, esters are derived from a carboxylic acid and an alcohol. Glycerides, which are fatty acid esters of glycerol, are important esters in biology, being one of the main classes of lipids, and making up the bulk of animal fats and vegetable oils. Esters with low molecular weight are commonly used as fragrances and found in essential oils and pheromones. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties, while polyesters are important plastics, with monomers linked by ester moieties. Acetone (systematically named 2-propanone) is the organic compound with the formula (CH)CO. It is a colorless, volatile, flammable liquid, and is the simplest ketone. Proteins (or ) are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific three-dimensional structure that determines its activity. Naphthenic acid (CAS: ) (NAs)is the name for an unspecific mixture of several cyclopentyl and cyclohexyl carboxylic acids with molecular weight of 120 to well over 700 atomic mass units. The main fraction are carboxylic acids with a carbon backbone of 9 to 20 carbons. McKee et al. claim that "naphthenic acids (NAs) are primarily cycloaliphatic carboxylic acids with 10 to 16 carbons." Salts of naphthenic acids, which are naphthenates, are widely used as hydrophobic sources of metal ions in diverse applications. Amino acids are biologically important organic compounds containing amine (-NH) and carboxyl (-COOH) functional groups, along with a side-chain (R group) specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, though other elements are found in the side-chains of certain amino acids. About 500 amino acids are known (though only 20 appear in the genetic code) and can be classified in many ways. They can be classified according to the core structural functional groups' locations as alpha- (-), beta- (-), gamma- (-) or delta- (-) amino acids; other categories relate to polarity, pH level, and side-chain group type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acids comprise the second-largest component (water is the largest) of human muscles, cells and other tissues. Outside proteins, amino acids perform critical roles in processes such as neurotransmitter transport and biosynthesis. Metabolism (from "metabol", "change") is the set of life-sustaining chemical transformations within the cells of living organisms. The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism. In chemistry, a ketone (alkanone) is an organic compound with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents. Ketones and aldehydes are simple compounds that contain a carbonyl group (a carbon-oxygen double bond). They are considered "simple" because they do not have reactive groups like OH or Cl attached directly to the carbon atom in the carbonyl group, as in carboxylic acids containing COOH. Many ketones are known and many are of great importance in industry and in biology. Examples include many sugars (ketoses) and the industrial solvent acetone, which is the smallest ketone. Pimaric acid is a carboxylic acid from the resin acid group . It can be prepared by dehydration of abietic acid , which it usually accompanies in mixtures like rosin . It is soluble in alcohols , acetone , and ethers . Terpenes are a large and diverse class of organic compounds, produced by a variety of plants, particularly conifers, though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their osmeteria. They often have a strong odor and may protect the plants that produce them by deterring herbivores and by attracting predators and parasites of herbivores. The difference between terpenes and terpenoids is that terpenes are hydrocarbons, whereas terpenoids contain additional functional groups. Abietic acid (also known as "abietinic acid" or "sylvic acid") is an organic compound that occurs widely in trees. It is the primary component of resin acid, is the primary irritant in pine wood and resin, isolated from rosin (via isomerization) and is the most abundant of several closely related organic acids that constitute most of rosin, the solid portion of the oleoresin of coniferous trees. Its ester or salt is called an "abietate".
candidates: a air alpha atom b carbon chemical compound chemical element chemistry code e egg et al . ethanol g group hydroxyl key lead metabolism nitroglycerin odor oil one oxygen periodic table plant polymer r ring run s salt second set smell solid sugars temperature tin tree δ
answer: carbon