Iodine-131 is a beta emitter used as a tracer in radio immunoassays biological systems. It follows first order kinetics. The half-life if iodine-131 is 8.04 dates. If you start with 8.0 grams of iodine-131, how many grams would remain at 39 days?

0.2774 grams of iodine-131 would remain at 39 days.

Explanation:

Initial concentration of iodine-131 =

Final concentration of iodine-131 after time t = [A] = ?

Duration of time = t = 39 days

Half life of the iodine-131 =

Rate constant =

For the first order kinetics :

[A] = 0.2774 g

0.2774 grams of iodine-131 would remain at 39 days.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.