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.

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 the ta…
292 questions
Questions where color (wavelengths associated with the visible region of the electromagnetic spectrum of about 400-800nm), or a color change is discussed.
281 questions
observed in the properties of elements as you move along the periodic table in a given direction.
279 questions
in solid phase, either in cases of their properties, or about ways of synthesizing them.
Questions regarding the chemical properties of hydrogen and its behavior in reactions and compounds.
249 questions
appropriate for reactions, their mechanisms, their kinetics, when catalysts of any kind are involved.
247 questions
For questions having their focus on SN1, SN2, SNi, SN1', SN2', or SN2th (nucleophilic acyl substitution).
A pure chemical substance consisting of a unique type of atom with a distinguished by its atomic mass.
245 questions
Compounds that have identical molecular formula but different chemical structure.
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…
234 questions
For questions about the thermodynamical state function entropy, commonly understood as a measure of disorder.
the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid
231 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.…
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…
221 questions
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…
213 questions
the enthalpy minus the product of thermodynamic temperature and entropy.
a branch of chemistry concerned with the chemical effects of ultraviolet, visible, or infrared radiation.
207 questions
For questions about gas pressure, or the effect of pressure in general on chemical species, substances, or reactions.
Chemical and physical characteristics of metals and alloys.
the temperature at which it changes state from solid to liquid.
201 questions
Applicable to questions about the ability of a molecule (or class of molecules) to be superimposed on their mirror image(s).
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…
199 questions
Bond between covalently bound hydrogen atom and atom possessing a lone pair of electrons.
195 questions
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…
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…
185 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…
185 questions
Questions about the application of chemistry to interrogate and modify biological systems and processes.
183 questions
Questions regarding the equipment used in labs (such as flasks, tubes etc.), their operation and maintenance.
182 questions
The description of the symmetry present in molecules. Molecular symmetry is useful for explaining or predicting of a molecule's chemical properties.
collective term for a set of laboratory techniques for the separation of mixtures
178 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.
171 questions
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 …
167 questions
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…
166 questions
roughly defined as the study of chemical reactions at interfaces between 2 or more phases.
166 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.
165 questions
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.
165 questions
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