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A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

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A liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature.
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observed in the properties of elements as you move along the periodic table in a given direction.
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A pure chemical substance consisting of a unique type of atom with a distinguished by its atomic mass.
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compounds containing only hydrogen and carbon atoms. This tag should be applied when a saturated or an unsaturated hydrocarbon is the main focus. For aromatic hydrocarbons, use [tag:a…
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Questions regarding the chemical properties of hydrogen and its behavior in reactions and compounds.
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in solid phase, either in cases of their properties, or about ways of synthesizing them.
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For questions about covalent compounds - which are compounds in which all intermolecular bonds between atoms are considered mostly covalent - have a stronger covalent than ionic or metallic component.…
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appropriate for reactions, their mechanisms, their kinetics, when catalysts of any kind are involved.
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a standard amount of a substance A mole of a substance is a number of units (particles, atoms, molecules, ions, peas, hard candies, people, universes) equal to the number of atoms of carbo…
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For questions about the thermodynamical state function entropy, commonly understood as a measure of disorder.
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the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid
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a branch of chemistry concerned with the chemical effects of ultraviolet, visible, or infrared radiation.
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Bond between covalently bound hydrogen atom and atom possessing a lone pair of electrons.
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For questions about amines - organic compounds with a basic nitrogen with a lone pair, also occasionally referred to as derivatives of ammonia. Not to be confused with amides, for which the tag [carbo…
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Compounds that have identical molecular formula but different chemical structure.
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the temperature at which it changes state from solid to liquid.
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Refers to ability for an atom in a covalent framework to attract electron density to itself. Do not conflate with electron affinity, which is the ability of a lone atom (or molecule) to attract an ele…
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should be applied to questions about the layout, history and interpretation of the periodic table, not to questions relating to specific elements or trends within the table. For these, the ta…
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represent qualities or quantities, elements or molecules, or formulas in general. Usually a notation follows a convention or a guideline, often published by IUPAC-I…
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Applicable to questions about the ability of a molecule (or class of molecules) to be superimposed on their mirror image(s).
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Chemical and physical characteristics of metals and alloys.
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Questions regarding the equipment used in labs (such as flasks, tubes etc.), their operation and maintenance.
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For questions about polar or non-polar chemical species, or their comparison. Also, for questions where polar or non-polar solvents have an effect.
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the enthalpy minus the product of thermodynamic temperature and entropy.
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For questions about determining Lewis structures (or their validity) for different chemical species. Do not use this tag if your question is about determining [oxidation-state] or [formal-charges], us…
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For questions about gas pressure, or the effect of pressure in general on chemical species, substances, or reactions.
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the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. Apply this tag to questions involving clarif…
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one of three classes of primary metabolites and thus natural products. They are polyhydroxylated hydrocarbons and their derivatives. Colloquially, they are known as sugars. This tag …
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Questions related to the physical combination of two or more substances on which the identities are retained and are mixed in the form of solutions, suspensions, and colloids.
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collective term for a set of laboratory techniques for the separation of mixtures
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species bearing a positive charge on carbon. They are intermediates generally formed during organic reactions, which can be stabilised by various electronic effects. Less stable carbo…
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Questions on the harmful effects of various substances on the human body, or biological organisms in general.
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Questions about the application of chemistry to interrogate and modify biological systems and processes.
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For questions having their focus on SN1, SN2, SNi, SN1', SN2', or SN2th (nucleophilic acyl substitution).
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For questions relating to organic compounds which contain a bond between a carbon atom and a metal.
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should be applied to questions about structural diagrams - diagrams used to show the crude location of possible existent bonds and lone pairs of electrons in a chemical species. Do not use th…