Beta Decay of Potassium-40

40K → 40Ca + e− + ν̄e

Visão geral

Potassium-40 decays to calcium-40 by beta emission (89.3%) or to argon-40 by electron capture (10.7%). With a half-life of 1.25 billion years, K-40 is the largest source of natural radioactivity in the human body. K-Ar dating is used for rocks millions to billions of years old.

Participantes

Papel Substância Coeficiente Estado
Reagente Potassium K 1 (s)
Produto Calcium Ca 1 (s)

Exemplo do cotidiano

Every human body contains about 4,400 Bq of K-40 radioactivity from potassium in food, primarily from bananas, potatoes, and meat.

Importância industrial

A datação K-Ar e Ar-Ar é utilizada para datar rochas vulcânicas e estabelecer escalas de tempo geológicas. O K-40 é também uma fonte de radiação de fundo na deteção de radiação.

Propriedades

Tipo
Nuclear
Reversível
Não
Energia
Exotérmico
ΔH
-130000000,0 kJ/mol

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Frequently Asked Questions

What is the equation for Beta Decay of Potassium-40?
The balanced equation is: ⁴⁰K → ⁴⁰Ca + e⁻ + ν̄ₑ.
What type of reaction is Beta Decay of Potassium-40?
Beta Decay of Potassium-40 is a nuclear reaction.
Is Beta Decay of Potassium-40 exothermic or endothermic?
Beta Decay of Potassium-40 is exothermic (releases energy). The enthalpy change (ΔH) is -130000000.0 kJ/mol.