Calculadora de Vida Media (Primer Orden) Gratis
Calcula la vida media de reacciones de primer orden. Independiente de la concentración inicial.
Half-Life (t½)
13.8629 s
Half-Life (t½) vs Rate Constant (k)
Fórmula
## First-Order Half-Life For a first-order reaction, the half-life is the time required for the concentration to decrease to half of its initial value. Uniquely for first-order kinetics, the half-life is independent of initial concentration. ### Formula **t½ = ln(2) / k = 0.693 / k** where k is the first-order rate constant. This formula applies to radioactive decay, drug metabolism, and many chemical decomposition reactions.
Ejemplo Resuelto
A first-order reaction with rate constant k = 0.05 s⁻¹.
- 01t½ = ln(2) / 0.05
- 02t½ = 0.6931 / 0.05 = 13.86 s
- 03In minutes: 13.86 / 60 = 0.231 min
Preguntas Frecuentes
Why is first-order half-life constant?
In a first-order reaction, the rate is proportional to concentration. As concentration halves, the rate also halves, so it always takes the same time to lose half of whatever remains. This is unique to first-order kinetics.
How many half-lives until the reaction is complete?
After 1 half-life: 50% remains. After 2: 25%. After 3: 12.5%. After 7 half-lives: less than 1% remains. The reaction never truly reaches zero but is practically complete after 5-7 half-lives.
Does this apply to radioactive decay?
Yes. Radioactive decay is a first-order process. The nuclear half-life formula t½ = ln(2)/lambda is mathematically identical, where lambda is the decay constant equivalent to k.
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