Search results for “pH”

Electrophile Organic Chemistry Dimensionless An electron-deficient species that seeks and accepts a pair of electrons from an electron-rich centre. E⁺

Electrophilic Addition Organic Chemistry Dimensionless A reaction in which an electrophile adds across a carbon–carbon multiple bond, converting a pi bond into two sigma bonds. C=C + E–Nu → C(E)–C(Nu)

Electrophilic Substitution Organic Chemistry Dimensionless A reaction in which an electrophile replaces a hydrogen atom on an aromatic ring. ArH + E⁺ → ArE + H⁺

Electrophoresis Analytical Chemistry & Spectroscopy cm/s A separation technique in which charged species migrate through a medium under an applied electric field. v = μE

Evaporation States of Matter & Gas Laws kJ/mol The escape of molecules from the surface of a liquid into the vapour phase below the boiling point.

E1 Reaction Organic Chemistry s⁻¹ A two-step elimination proceeding through a carbocation, which then loses a proton to form an alkene. rate = k[substrate]

Ebullioscopic Constant Solutions & Colligative Properties K·kg/mol The boiling point elevation produced by a one-molal solution of a non-electrolyte in a given solvent. K_b = RT_b²M / ΔH_vap

Electrode Electrochemistry & Redox Dimensionless A conductor through which electric current enters or leaves an electrolyte.

Electrolyte Electrochemistry & Redox S/m A substance that produces mobile ions when dissolved or molten and therefore conducts electricity.

Emulsion Solutions & Colligative Properties nm A colloidal dispersion of one liquid as fine droplets throughout another liquid with which it is immiscible.

Enantiomer Organic Chemistry degrees One of a pair of stereoisomers that are non-superimposable mirror images of each other. (+) and (−), or R and S

Endergonic Reaction Thermochemistry & Thermodynamics kJ/mol A reaction with a positive Gibbs free energy change, which requires an input of energy to proceed. ΔG > 0

Enthalpy Thermochemistry & Thermodynamics kJ/mol A thermodynamic state function equal to internal energy plus the product of pressure and volume. H = U + pV

Enthalpy of Sublimation Thermochemistry & Thermodynamics kJ/mol The enthalpy change when one mole of a solid converts directly into vapour. ΔH_sub = ΔH_fus + ΔH_vap

Enzyme Biochemistry & Polymer Chemistry Dimensionless A biological catalyst, almost always a protein, that accelerates a specific biochemical reaction.

Enzyme Catalysis Chemical Kinetics & Catalysis Dimensionless Catalysis by protein molecules that bind substrates at a specific active site and lower the activation energy dramatically.

Equivalence Point Acids, Bases & Salts mol The point in a titration at which exactly stoichiometric amounts of the two reactants have been combined. n_acid × basicity = n_base × acidity

Element Foundations of Chemistry Dimensionless A pure substance composed entirely of atoms that share the same atomic number and therefore cannot be split into simpler substances by chemical means.

End Point Acids, Bases & Salts mL The point in a titration at which the indicator changes colour, signalling that the reaction is judged complete.

Endothermic Reaction Stoichiometry & Chemical Reactions kJ/mol A reaction that absorbs energy from the surroundings, giving a positive enthalpy change. ΔH > 0

Results for “pH”