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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.

For questions having their focus on SN1, SN2, SNi, SN1', SN2', or SN2th (nucleophilic acyl substitution).
375 questions
Questions where color (wavelengths associated with the visible region of the electromagnetic spectrum of about 400-800nm), or a color change is discussed.
366 questions
For questions about the thermodynamical state function entropy, commonly understood as a measure of disorder.
362 questions
Trends which are observed in the properties of elements as you move along the periodic table in a given direction.
360 questions
Study of chemical species that are in solid phase, either in cases of their properties, or about ways of synthesizing them.
359 questions
Questions regarding the chemical properties of hydrogen and its behavior in reactions and compounds.
350 questions
appropriate for reactions, their mechanisms, their kinetics, when catalysts of any kind are involved.
321 questions
Compounds that have identical molecular formula but different chemical structure.
318 questions
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…
314 questions
The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid
305 questions
Also known as Gibbs energy, it is the enthalpy minus the product of thermodynamic temperature and entropy.
300 questions
For questions about gas pressure, or the effect of pressure in general on chemical species, substances, or reactions.
300 questions
A pure chemical substance consisting of a unique type of atom with a distinguished by its atomic mass.
297 questions
This is 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…
285 questions
collective term for a set of laboratory techniques for the separation of mixtures
285 questions
Chemical and physical characteristics of metals and alloys.
276 questions
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.…
275 questions
Intermolecular force between covalently bound hydrogen atom and atom possessing a lone pair of electrons.
265 questions
A system of written symbols used to 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…
263 questions
Photochemistry is a branch of chemistry concerned with the chemical effects of ultraviolet, visible, or infrared radiation.
262 questions
The mole is 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…
259 questions
Applicable to questions about the ability of a molecule (or class of molecules) to be superimposed on their mirror image(s).
258 questions
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…
257 questions
The description of the symmetry present in molecules. Molecular symmetry is useful for explaining or predicting of a molecule's chemical properties.
251 questions
The melting point of a solid is the temperature at which it changes state from solid to liquid.
248 questions
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…
241 questions
Mass spectrometry (MS) is an analytical technique which takes advantage of the mass-to-charge ratio of gas-phase ions in order to elucidate the composition of a sample.
240 questions
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.
235 questions
Questions about the application of chemistry to interrogate and modify biological systems and processes.
232 questions
For questions about the various atomic structure theories, including the Bohr theory. Not to be confused with the actual arrangement of atoms in macroscopic solids ([solid-state-chemistry]) or newer q…
231 questions
Surface chemistry is roughly defined as the study of chemical reactions at interfaces between 2 or more phases.
230 questions
Questions regarding the equipment used in labs (such as flasks, tubes etc.), their operation and maintenance.
230 questions
For questions relating to organic compounds which contain a bond between a carbon atom and a metal.
226 questions
For questions about polar or non-polar chemical species, or their comparison. Also, for questions where polar or non-polar solvents have an effect.
223 questions
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…
223 questions
Carbocations are 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…
222 questions
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