Chemistry — Data Booklet
All values provided in the exam. First assessment 2025.
Section 1 — Physical Constants
These values are exact as given in the IB 2025 Chemistry Data Booklet.
| Constant | Symbol | Value | Units |
|---|---|---|---|
| Avogadro's constant | NA | 6.02 × 1023 | mol−1 |
| Gas constant | R | 8.31 | J K−1 mol−1 |
| Boltzmann constant | kB | 1.38 × 10−23 | J K−1 |
| Planck's constant | h | 6.63 × 10−34 | J s |
| Speed of light (vacuum) | c | 3.00 × 108 | m s−1 |
| Elementary charge | e | 1.60 × 10−19 | C |
| Electron mass | me | 9.11 × 10−31 | kg |
| Molar volume of ideal gas at STP (273.15 K, 100 kPa) | Vm | 22.7 | dm3 mol−1 |
| Standard atmospheric pressure | p⊙ | 101.3 | kPa |
| Ionic product of water (298 K) | Kw | 1.0 × 10−14 | mol2 dm−6 |
Click any value to copy it to the clipboard.
Section 2 — Periodic Table
Showing atomic number, symbol, and relative atomic mass (Ar). Click any element for details.
Section 3 — Key Equations
All equations below are provided in the data booklet. Understand when and how to apply each one.
Ideal Gas Law
P = pressure (Pa), V = volume (m³), n = moles, R = 8.31 J K⁻¹ mol⁻¹, T = temperature (K)
Combined Gas Law
Relates gas state at two different conditions. Temperature must be in kelvin.
Concentration
c in mol dm⁻³, n in mol, V in dm³. Also written as [X] for species X.
pH
[H⁺] is the molar concentration of hydrogen ions in mol dm⁻³.
pKw
Valid at 298 K (25 °C). Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴ mol² dm⁻⁶
Henderson–Hasselbalch
Buffer equation. [A⁻] = conjugate base concentration, [HA] = weak acid concentration.
Gibbs Free Energy
ΔG < 0: spontaneous. Units: kJ mol⁻¹. T in kelvin, ΔS in kJ K⁻¹ mol⁻¹ (watch units!).
Gibbs & Equilibrium
Links thermodynamics to the equilibrium constant K. Standard state (°) at 298 K.
Arrhenius Equation
k = rate constant, A = pre-exponential factor, Ea = activation energy (J mol⁻¹).
First-Order Integrated Rate Law
Also written as ln[A] = −kt + ln[A]₀. Half-life: t½ = ln2 / k.
Beer–Lambert Law
A = absorbance (no units), ϵ = molar absorptivity, c = concentration, l = path length (cm).
Section 4 — Average Bond Enthalpies
Average values in kJ mol⁻¹ at 298 K. Used to estimate enthalpy changes: ΔH ≈ Σ(bonds broken) − Σ(bonds formed).
| Bond | Energy / kJ mol⁻¹ | Bond | Energy / kJ mol⁻¹ |
|---|---|---|---|
| C–H | 413 | O–H | 463 |
| C–C | 347 | O=O | 498 |
| C=C | 614 | N–H | 391 |
| C≡C | 839 | N≡N | 945 |
| C=O | 799 | H–H | 436 |
| C–O | 358 | Cl–Cl | 242 |
| C–Cl | 346 | C–Br | 285 |
Section 5 — Electronegativity (Pauling Scale)
Values for elements commonly encountered in IB Chemistry SL.
| Element | Symbol | Electronegativity |
|---|---|---|
| Fluorine | F | 3.98 |
| Oxygen | O | 3.44 |
| Chlorine | Cl | 3.16 |
| Nitrogen | N | 3.04 |
| Bromine | Br | 2.96 |
| Sulfur | S | 2.58 |
| Carbon | C | 2.55 |
| Iodine | I | 2.66 |
| Hydrogen | H | 2.20 |
| Phosphorus | P | 2.19 |
| Magnesium | Mg | 1.31 |
| Sodium | Na | 0.93 |
Section 6 — Unit Conversions & SI Prefixes
SI Prefixes
| Prefix | Symbol | Factor |
|---|---|---|
| tera | T | 1012 |
| giga | G | 109 |
| mega | M | 106 |
| kilo | k | 103 |
| deci | d | 10−1 |
| centi | c | 10−2 |
| milli | m | 10−3 |
| micro | μ | 10−6 |
| nano | n | 10−9 |
| pico | p | 10−12 |
Key Conversions
| Quantity | Conversion |
|---|---|
| Pressure | 1 atm = 101.3 kPa = 760 mmHg |
| Temperature | 0 °C = 273.15 K (ΔT in °C = ΔT in K) |
| Volume | 1 dm³ = 1 L = 1000 cm³ = 1000 mL |
| Energy | 1 kJ = 1000 J |