The element weirdium (We), found only on the planet Crosbia has only two isotopes; We-60 (60.00 amu) and We-90 (90.00 amu)! The average atomic mass of a naturally occurring sample
of weirdium is 70.00 amų. Calculate the percent abundance of We-60.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

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.

50.23 i believe is correct but don't quote me on that.