If you had a 100-gram sample of plutonium, how much would still remain in 43 years?

1 Answer
Jun 7, 2016

Answer:

#m_r~=11.9 \ grams#

Explanation:

What is missing from the question is the identity of the specific isotope present in the 100-gram sample - I would assume it is plutonium - 241 that has an average half-life of 14 years, the shortest among the plutonium isotopes family.

# n " is the number of periods "#

#n=(time)/("half-life")#

#n= (43 \ "years")/ (14 \ "years")~=3.07#

#m_i=m_rxx2^n#

#m_i=" is the initial mass"#

#m_r=" is the remaining mass after n periods"#

#m_r=m_i/2^n#

#m_r=100/2^(3.07)#

#m_r~=11.9 \ grams#