Chapter 19, Problem 19.78QP

Interpretation Introduction

Interpretation: Number of atoms present in the Iodine -131 should be calculated

Concept Introduction:

• Half-life period: The time required to reduce the half of its original value.
• This is denoted by:${\text{t}}_{\text{1/2}}$
• This term is popularly use in nuclear chemistry, to describe the stability & instability of atoms or radioactive decay.
• For determination of first order rate constant K in half –life period we use

  $\text{K=}\frac{\text{0}\text{.693}}{{\text{t}}_{\text{1/2}}}$  Equation.

• The half-life in first order does not depend upon the initial concentration.

  Formula:

• Age calculation:

  $\text{ln}\frac{{\text{N}}_{\text{t}}}{{\text{N}}_{\text{0}}}\text{=-kt}$

• Calculate the age and rate constant:

  $\text{K=}\frac{\text{0}\text{.693}}{{\text{t}}_{\text{1/2}}}$

To Determine: Number of atoms present in the Iodine -131 by using the given data.

Given:

Half-life period of ${\text{I}}^{\text{131}}$=8.1days.