Approximately what percentage of Rb-87 will have decayed to Sr-87 when the rock is 3 billion years old? After 0.02 half-
lives
After 0.04 half-
lives
After 0.06 half-
lives
After 0.08 half-
lives
percent of Rb-87
remaining
98.623
97.265
95.926
94.606

confused

confused             hewdejdnjnjsnd

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.