Arrhenius Activation Energy (Rate vs Temperature)
The rate-vs-temperature member the lab kinetics set (doubling-time, Michaelis-Menten) was missing.
Example
You enter
- Rate constant k1 1
- Temperature 1 (°C) 25
- Rate constant k2 2
- Temperature 2 (°C) 35
You get
- Activation energy Ea 52.95
- Q10 temperature coefficient 2
Details, formula, and sources
From two rate constants at two temperatures: Ea = R ln(k2/k1)/(1/T1 - 1/T2), R = 8.314 J/(mol*K), T in kelvin, then the pre-exponential A = k1 exp(Ea/(R T1)) and k at any T = A exp(-Ea/RT). A reaction that doubles from 25 to 35 C has Ea 52.9 kJ/mol and A 1.9e9. Also reports the Q10 temperature coefficient (rate change per 10 C; Q10 2 = doubles). Assumes a single mechanism over the interval. A first-principles chemistry aid.
k = A exp(-Ea/RT); two-point Ea = R ln(k2/k1)/(1/T1 - 1/T2), R = 8.314 J/(mol*K), T in kelvin; A = k1 exp(Ea/(R T1)); Q10 = (k2/k1)^(10/dT_C).
The Arrhenius equation (Arrhenius, 1889); standard physical-chemistry kinetics. First principles.
The Arrhenius equation and the gas constant R are public first-principles chemistry; the rate constants and temperatures are the user's own measurements.
Verify protocol against your lab's SOP before pipetting. A miscalculated dilution can ruin a run or a sample.
Field names used by the API: k1, temp1_c, k2, temp2_c, ea_kj_mol, q10
- Arrhenius equation k = A exp(-Ea/RT); Ea = R ln(k2/k1)/(1/T1 - 1/T2)Arrhenius (1889)
- Derived A = k1 exp(Ea/(R T1)); Q10 = (k2/k1)^(10/dT_C)kinetics
- Scope single mechanism over the interval (a curved Arrhenius plot signals a mechanism change)scope of this tile