Meia-vida (1ª ordem)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
t½
About this calculator
The First-Order Half-Life Calculator is a useful tool for chemists and engineers working with chemical reactions. It calculates the half-life of a substance, which is the time required for the concentration of the substance to decrease to half of its initial concentration.
The underlying formula for calculating half-life is t½ = ln(2)/k, where t½ is the half-life, ln(2) is the natural logarithm of 2, and k is the reaction rate constant.
This calculator is particularly useful in cases where the reaction is of first order, meaning the reaction rate is directly proportional to the concentration of the substance. This is common in chemical reactions involving the formation or decomposition of substances.
However, it is essential to remember that half-life is a quantity that depends on temperature, pressure, and other experimental conditions. Therefore, it is crucial to consider these factors when interpreting the results of the calculator.
Frequently asked questions
What is half-life?
Half-life is the time required for the concentration of a substance to decrease to half of its initial concentration.
When to use this calculator?
Use this calculator in cases where the reaction is of first order and you need to calculate the half-life of a substance.
What is the reaction rate constant?
The reaction rate constant (k) is a constant that determines the rate of the reaction. It is usually expressed in units of time^-1.
Can I use this calculator with other formulas?
No, this calculator is designed to calculate the half-life of a substance using the formula t½ = ln(2)/k. If you need to use another formula, you need to create a custom calculator.
What happens if the reaction rate constant is zero?
If the reaction rate constant (k) is zero, the half-life will be infinite. This means that the reaction is very slow or does not occur.