Search results for “pH”

pH Acids, Bases & Salts Dimensionless The negative logarithm to base ten of the hydrogen ion concentration, measuring the acidity of a solution. pH = −log[H⁺]

pH Scale Acids, Bases & Salts Dimensionless The conventional scale, usually running from 0 to 14, on which the acidity or alkalinity of aqueous solutions is expressed. 0 (acidic) – 7 (neutral) – 14 (alkaline)

Phase Diagram States of Matter & Gas Laws Pa, K A pressure–temperature plot showing which phase of a substance is thermodynamically stable under any given conditions.

Phase Equilibrium Chemical Equilibrium Dimensionless The condition in which two or more phases of a substance coexist with no net transfer between them. μ_phase1 = μ_phase2

Phenol Organic Chemistry Dimensionless A compound in which a hydroxyl group is bonded directly to an aromatic ring. C₆H₅–OH

Phenolphthalein Acids, Bases & Salts Dimensionless An acid–base indicator that is colourless in acid and pink in alkaline solution, changing between pH 8.3 and 10.0. C₂₀H₁₄O₄

Phospholipid Biochemistry & Polymer Chemistry Dimensionless A lipid in which one fatty acid of a triglyceride is replaced by a phosphate-containing group.

Photochemical Quantum Yield Chemical Kinetics & Catalysis Dimensionless The number of molecules reacting for each photon of light absorbed by the system. Φ = molecules reacted / photons absorbed

Photochemical Reaction Stoichiometry & Chemical Reactions nm A reaction initiated by the absorption of light, which promotes a molecule to an electronically excited state. A + hν → A*

Photosynthesis Biochemistry & Polymer Chemistry kJ/mol The process by which plants use light energy to convert carbon dioxide and water into carbohydrate and oxygen. 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Physical Change Foundations of Chemistry Dimensionless A change that alters the form or state of a substance while leaving its chemical composition intact.

Physical Equilibrium Chemical Equilibrium Dimensionless An equilibrium between two physical states or phases of the same substance. H₂O(l) ⇌ H₂O(g)

Physical Property Foundations of Chemistry Various A characteristic of a substance that can be observed or measured without altering its chemical identity.

Physisorption Chemical Kinetics & Catalysis kJ/mol Weak adsorption in which molecules are held to a surface by van der Waals forces alone. ΔH ≈ −20 to −40 kJ/mol

Adenosine Triphosphate Biochemistry & Polymer Chemistry kJ/mol The nucleotide that acts as the universal energy currency of living cells. ATP + H₂O → ADP + Pᵢ

Alpha Decay Nuclear & Radiochemistry MeV Radioactive decay in which a nucleus emits a helium-4 nucleus, losing two protons and two neutrons. ᴬ_Z X → ᴬ⁻⁴_Z₋₂ Y + ⁴₂He

Amorphous Solid States of Matter & Gas Laws Dimensionless A solid whose particles lack long-range order, showing only the short-range regularity characteristic of a frozen liquid.

Amphiprotic Species Acids, Bases & Salts Dimensionless A species that can both donate and accept a proton.

Amphoteric Substance Acids, Bases & Salts Dimensionless A substance able to react as either an acid or a base depending on what it meets.

Chromatography Analytical Chemistry & Spectroscopy Dimensionless A family of separation techniques that partition components between a stationary and a mobile phase.

Chromophore Analytical Chemistry & Spectroscopy nm The part of a molecule responsible for absorbing light at a particular wavelength.

Column Chromatography Analytical Chemistry & Spectroscopy g A preparative technique in which a mixture is separated by passing it down a vertical column packed with stationary phase.

Coordination Sphere Inorganic & Coordination Chemistry Dimensionless The central metal together with the ligands directly attached to it, written inside square brackets. [M(L)ₙ]

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

Results for “pH”