Plutonium-238, atomic mass 238.050 g/mol, is a radioisotope that undergoes the following first-order decay with a half-life of 87.74 years. Pu-238 decays to U-234 + He . The alpha particle from Pu-238 is ejected with an energy of 5.593 MeV per particle. The spacecraft left earth on October 15, 1997. The spacecrafts radioisotope thermoelectric generators must have a rate of decay of no less than 1.44 x 10^16 Pu-238 atoms per second.
Problems:
1) Calculate the minimum mass of Pu-238 (in kilograms) that would had to have been loaded on the spacecraft at the time of its launch from earth.
2) What was the instantaneous rate of decay (in mg/sec) at the time of launch from earth?
3) How much energy will have been released (in kJ) from the time of the spacecrafts launch until April 19, 2012 (5301 days)? (1 eV = 1.60218 x 10^-19 J).