Methodology & per-tool citation index
Every tool on Chemkit traces its physical constants, atomic weights, textbook worked examples, and unit-conversion factors back to a primary or tertiary reference. This page is the citation index — one card per tool, with the sources it uses and the canonical worked example it was tested against.
Global sources (used across every tool)
- Physical constants — CODATA 2018 recommended values, published by NIST (physics.nist.gov/cuu/Constants). Includes R, F, kB, NA.
- Atomic weights — IUPAC 2021 conventional values (Prohaska et al., Pure Appl. Chem. 94:573, 2022). Bracket-form values are used where IUPAC publishes a bracket.
- Unit conversions — NIST Special Publication 811 (2008 rev.). Pressure, energy, length, and volume factors are all from SP 811 tables.
- Temperature — ITS-90 conventions. K = °C + 273.15 exactly; K = (°F + 459.67) × 5/9 exactly.
- Ionization constant of water — CRC Handbook of Chemistry and Physics, 97th ed. (2016). Rounded to Kw = 1.0 × 10⁻¹⁴ at 25 °C.
Per-tool references
Molarity Calculator
- Category
- general
- Primary sources
- Zumdahl §4.3; IUPAC Gold Book (amount concentration); PubChem CIDs for cited MWs
- Canonical worked example
- 0.500 M NaCl in 2.00 L → 58.4 g (Zumdahl 10e §4.3)
Dilution Calculator
- Category
- general
- Primary sources
- Harris QCA 10e §1-3; IUPAC Gold Book (dilution)
- Canonical worked example
- 12 M HCl → 3.0 M in 100 mL: draw 25 mL stock (Harris 10e §1-3)
Molar Mass Calculator
- Category
- general
- Primary sources
- IUPAC 2021 atomic weights (CIAAW); PubChem for compound cross-checks
- Canonical worked example
- CuSO₄·5H₂O = 249.68 g/mol (PubChem CID 24463)
Buffer Calculator
- Category
- general
- Primary sources
- Good et al. Biochemistry 5 (1966) 467; Good & Izawa Meth. Enzymol. 24 (1972) 53; CRC 97e
- Canonical worked example
- 0.10 M acetate, pH 5.00 → [A⁻]/[HA] = 1.74 (Harris 10e §9)
Serial Dilution Calculator
- Category
- general
- Primary sources
- Harris QCA 10e §1-3; Rainin/Gilson pipette accuracy specs
- Canonical worked example
- 1 M → 10 nM in 4 × 10-fold steps at 100 µL/step
Ideal Gas Law Calculator
- Category
- physical
- Primary sources
- CODATA 2018 (R exact by SI); NIST SP 811 pressure factors; Atkins §1B
- Canonical worked example
- 0.500 mol, 5.00 L, 25 °C → P ≈ 2.447 atm (Atkins 12e §1B)
pH Calculator
- Category
- analytical
- Primary sources
- Harris QCA 10e §8-1 through §8-4; Zumdahl 10e §14; CRC 97e (Kw)
- Canonical worked example
- 0.10 M acetic acid, pKa 4.76 → pH ≈ 2.87 (Harris 10e §8-3)
Percent Solution Calculator
- Category
- general
- Primary sources
- Harris QCA 10e §1-4; IUPAC Gold Book (mass concentration, volume fraction)
- Canonical worked example
- 0.9 % (w/v) NaCl (physiological saline)
Percent Yield Calculator
- Category
- general
- Primary sources
- Zumdahl 10e §3.10; Harris QCA 10e §7
- Canonical worked example
- Salicylic acid → aspirin, 6.9 g SA → 7.5 g product (83.3 % yield)
Dilution Factor Calculator
- Category
- general
- Primary sources
- Harris QCA 10e §1-3; Cold Spring Harbor Protocols dilution guides
- Canonical worked example
- 1:100 dilution: 10 µL stock into 1.0 mL final
Normality Calculator
- Category
- analytical
- Primary sources
- Harris QCA 10e §7-4; Skoog 10e §4B; IUPAC 1980 Recommendation (Pure Appl. Chem. 51, 1213)
- Canonical worked example
- 0.500 M H₂SO₄ × z = 2 → 1.00 N (Harris 10e §7-4)
Beer-Lambert Calculator
- Category
- analytical
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Limiting Reagent Calculator
- Category
- general
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Nernst Equation Calculator
- Category
- physical
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Half-Life Calculator
- Category
- physical
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Degrees of Unsaturation Calculator
- Category
- organic
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Ksp / Molar Solubility Calculator
- Category
- inorganic
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Michaelis-Menten Calculator
- Category
- biochem
- Primary sources
- See the tool page's sources block.
- Canonical worked example
- See tool page.
Textbook shortlist
These titles are the standing references for worked-example verification:
- Harris, Daniel C. Quantitative Chemical Analysis, 10th ed. W.H. Freeman, 2020.
- Zumdahl, Steven S. & Susan A. Zumdahl. Chemistry, 10th ed. Cengage Learning, 2018.
- Atkins, Peter & Julio de Paula. Physical Chemistry, 12th ed. Oxford University Press, 2022.
- Skoog, Douglas A., Donald M. West, F. James Holler, & Stanley R. Crouch. Fundamentals of Analytical Chemistry, 10th ed. Cengage, 2022.
- Silberberg, Martin. Chemistry: The Molecular Nature of Matter and Change, 9th ed. McGraw-Hill, 2020.
Sourcing standards for future tools
A calculator does not ship until every value it uses is either:
- Derived exactly from an SI redefinition (e.g., NA, kB, R), or
- Cited in a comment in its source file (e.g.,
src/lib/chemistry/constants.ts), naming the reference (NIST, IUPAC, CRC, PubChem CID, Sigma spec sheet) with edition or year, or - Computed from other cited values (e.g., MW is computed from IUPAC 2021 atomic weights via
src/lib/chemistry/formula-parser.tsandperiodic-table.ts).
If a chemistry fact is ambiguous, we stop and ask before implementing. A wrong calculation permanently damages the credibility of a site whose whole product is being the correct reference.