Answer:
0.2g
Explanation:
All radiodecay follows the 1st order decay equation
A = A₀e^-kt
A => Activity at time (t)
A₀ => Initial Activity at time = 0
k => decay constant for isotope
T => time in units that match the decay constant
Half-Life Equation => kt(½) = 0.693 => k = 0.693/34 min = 0.0204min¹
A = A₀e^-kt = (26g)e^-(0.0204/min)(238min) = (26g)(0.0078) = 0.203g ~ 0.2g (1 sig fig).