{ "model": { "rank": 9397, "code": "thing-q325519", "model_id": "vr.tr.acid-dissociation-constant", "name": "acid dissociation constant", "purpose": "Let an agent explain acid dissociation constants and pKa, compute pH, degree of dissociation and buffer behaviour, find values with sources, and relate pKa to molecular structure.", "family": "Thing Registry", "category": "Cross-cutting context", "status": "research-draft", "kind": "thing", "plane": "XCT", "domain": "XCT.QTY", "industry": "", "version": "", "url": "/models/thing/q325519/", "tier": 2, "score": 47, "payload": { "layer": "wikidata", "aliases": [], "aliasCount": 0, "merged": 0, "knownIn": 47, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": null, "source": { "dataset": "wikidata", "item": "Q325519", "url": "https://www.wikidata.org/wiki/Q325519", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-11T23:04:33Z", "providers": [ "Claude" ], "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify", "pass": 2, "wave": 2, "engine": "claude" }, "metaModel": { "id": "THING-Q325519", "registryId": "vr.tr.acid-dissociation-constant", "name": "acid dissociation constant", "version": "0.2.0-wave.2", "entryKind": "thing", "family": "Thing Registry", "domain": [ "XCT.QTY" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q325519/", "model": { "registry_id": "vr.tr.acid-dissociation-constant", "name": "acid dissociation constant", "purpose": "Let an agent explain acid dissociation constants and pKa, compute pH, degree of dissociation and buffer behaviour, find values with sources, and relate pKa to molecular structure.", "definition": "The equilibrium constant for the dissociation of an acid into a proton and its conjugate base in solution, denoted Ka and usually expressed as its negative logarithm pKa, quantifying acid strength so that lower pKa means a stronger acid; acid dissociation constants depend on temperature and solvent and are used in buffer design, drug chemistry, environmental chemistry and biochemistry.", "what_it_is_for": "Quantifying acid strength.", "affordances": [ "explain Ka and pKa", "compute pH and buffers", "find values with sources", "relate pKa to structure" ], "distinguishing_features": [ "Acid-specific", "Logarithmic pKa form", "Condition-dependent", "Structure-related" ], "appearance": "Not physical; a numerical constant.", "visual_identification": [ "Equilibrium constant for acid dissociation", "Expressed as pKa", "Kb describes base dissociation" ], "physical_properties": [], "families_and_kinds": [ "pKa of strong and weak acids", "polyprotic acid constants", "pKa of amino acids and drugs", "apparent pKa in mixed solvents", "temperature-dependent constants" ], "related_models": [ { "relation": "is a kind of", "target": "dissociation constant", "why": "category" }, { "relation": "is a kind of", "target": "acid strength", "why": "category" }, { "relation": "is related to", "target": "solution", "why": "aqueous equilibria" }, { "relation": "is related to", "target": "chemical property", "why": "acid strength as a property" } ], "identifiers": [], "standards_and_regulation": [ "IUPAC conventions on equilibrium constants", "Standard conditions for reporting pKa", "Pharmaceutical guidelines on pKa determination" ], "failure_modes_and_hazards": [ "Confusing Ka and pKa direction", "Ignoring temperature and ionic strength", "Misapplying to strong acids" ], "in_scope": [], "out_of_scope": [], "characteristics": [] }, "sources": [], "structure": { "bundles": [ { "id": "understand", "name": "Understand", "description": "What pKa means.", "rationale": "Concepts.", "layers": [ { "id": "meaning", "name": "Meaning", "description": "Ka and pKa.", "findings": [ { "id": "meaning-finding", "name": "Meaning", "description": "Meaning.", "questions": [ { "text": "What are Ka and pKa, and how do they express acid strength?", "kind": "definition" }, { "text": "How do pKa and pKb of conjugate pairs relate?", "kind": "definition" } ] } ] }, { "id": "structure", "name": "Structure", "description": "Structure and acidity.", "findings": [ { "id": "structure-finding", "name": "Structure", "description": "Structure.", "questions": [ { "text": "How do molecular structure, electronegativity, resonance and solvent affect pKa?", "kind": "definition" }, { "text": "Why do polyprotic acids have several pKa values?", "kind": "definition" } ] } ] } ] }, { "id": "compute", "name": "Compute", "description": "Calculations.", "rationale": "Practice.", "layers": [ { "id": "ph", "name": "pH", "description": "pH and dissociation.", "findings": [ { "id": "ph-finding", "name": "pH", "description": "pH.", "questions": [ { "text": "What is the pH or degree of dissociation of this acid solution, given its pKa and concentration?", "kind": "action" }, { "text": "How is the Henderson-Hasselbalch equation used?", "kind": "action" } ] } ] }, { "id": "buffers", "name": "Buffers", "description": "Buffer design.", "findings": [ { "id": "buffers-finding", "name": "Buffers", "description": "Buffers.", "questions": [ { "text": "How is a buffer designed at a target pH using pKa?", "kind": "action" }, { "text": "What determines buffer capacity?", "kind": "definition" } ] } ] } ] }, { "id": "measure", "name": "Measure", "description": "Values and methods.", "rationale": "Sources.", "layers": [ { "id": "lookup", "name": "Lookup", "description": "Finding pKa values.", "findings": [ { "id": "lookup-finding", "name": "Lookup", "description": "Lookup.", "questions": [ { "text": "What is the pKa of this acid, according to reference data, and under which conditions?", "kind": "provenance" }, { "text": "Which databases apply?", "kind": "provenance" } ] } ] }, { "id": "methods", "name": "Methods", "description": "Measuring pKa.", "findings": [ { "id": "methods-finding", "name": "Methods", "description": "Methods.", "questions": [ { "text": "How is pKa measured by titration, spectroscopy and computation?", "kind": "provenance" }, { "text": "How reliable are predicted values?", "kind": "boundary" } ] } ] } ] }, { "id": "apply", "name": "Apply", "description": "Applications and teaching.", "rationale": "Context.", "layers": [ { "id": "applications", "name": "Applications", "description": "pKa in practice.", "findings": [ { "id": "applications-finding", "name": "Applications", "description": "Applications.", "questions": [ { "text": "How is pKa used in drug design, environmental chemistry and biochemistry?", "kind": "provenance" }, { "text": "Which entry fits a specific acid?", "kind": "action" } ] } ] }, { "id": "teach", "name": "Teach", "description": "Teaching.", "findings": [ { "id": "teach-finding", "name": "Teach", "description": "Teaching.", "questions": [ { "text": "How can acid dissociation constants be taught with titration curves?", "kind": "action" }, { "text": "Which misconceptions arise?", "kind": "provenance" } ] } ] } ] } ] }, "openQuestions": [ "Should pKa tables be linked per compound?", "How should databases be linked?", "How should measurement methods be linked?" ], "statistics": { "bundles": 4, "layers": 8, "findings": 8, "questions": 16 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "unit, quantity or measure", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a acid dissociation constant, record what state it is in, and decide what may be done with it.", "whatItIs": "Let an agent explain acid dissociation constants and pKa, compute pH, degree of dissociation and buffer behaviour, find values with sources, and relate pKa to molecular structure.", "characteristics": { "substance": "abstract", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "observed and measured" ], "distinguishingFeatures": [ "Described in 47 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a acid dissociation constant, and on what evidence are they told apart?" ], "whatItIsMadeOf": "an abstraction with no physical instance", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "observe it, measure it, record its state" ], "howItIsRecognised": [ "Nothing to see: a unit is a convention. What is seen is an instrument reading in it." ], "relatedModels": [], "standing": "Described in 47 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one acid dissociation constant from another, and a acid dissociation constant from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a acid dissociation constant sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a acid dissociation constant from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a acid dissociation constant passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a acid dissociation constant between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a acid dissociation constant, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a acid dissociation constant is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "definition-and-realisation", "name": "Definition, dimension and realisation", "description": "What acid dissociation constant is defined as and how it is realised in practice.", "rationale": "A unit is not the quantity it measures, and its definition has a history that older data still depends on.", "layers": [ { "id": "definition", "name": "Definition and dimension", "description": "The defining relation and the quantity it measures.", "findings": [ { "id": "definition-record", "name": "Definition, body and date", "description": "What defines it now, and what defined it before.", "questions": [ { "id": "definition-record-q01", "text": "How is acid dissociation constant defined, by which body, and since when?", "kind": "definition" }, { "id": "definition-record-q02", "text": "What was the previous definition, and what data still depends on it?", "kind": "provenance" } ] } ] }, { "id": "conversion", "name": "Conversion and compatibility", "description": "Relations to other units, exact or approximate.", "findings": [ { "id": "conversion-record", "name": "Conversions and their exactness", "description": "Factors, and whether each is exact by definition.", "questions": [ { "id": "conversion-record-q01", "text": "What conversions relate acid dissociation constant to other units, and which are exact by definition?", "kind": "measurement" }, { "id": "conversion-record-q02", "text": "Where does rounding a conversion change a decision, and how should that be recorded?", "kind": "action" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a acid dissociation constant came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a acid dissociation constant and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a acid dissociation constant is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a acid dissociation constant, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a acid dissociation constant, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a acid dissociation constant is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 4, "layers": 8, "findings": 10, "questions": 28 } } } }