a. Bismuth-214 decays by alpha emission with a half-life of 19.7minutes. If 15.0 grams of Bismuth-214 is placed in a sealed vessel,what mass of the Bismuth will have decayed after 35.0 minutes?
b. How long will it take for a sample of carbon-14 to decay suchthat only 70% of the original sample of carbon-14 remains?
c. In a process called \"positron-electron annihilation,\" apositron collides with an electron, and both particles aredestroyed. During this process, the total mass of both particles iscompletely converted to energy in the form of gamma radiation.Determine the total energy given off when one positron collideswith one electron resulting in annihilation. (Note: mass ofpositron = mass of electron = 0.000549 amu)
