Ba-122 has half-life of 2 ~min . Experiment has to be done using B a-122 and it takes 10 min to set up the experiment. It initially 80 ~g at Ba -122 was taken, how much Ba was left when experiment was started?

Step-by-step solution

The half-life of Ba-122 is given as T_ 1/2 = 2 min . The time elapsed before the experiment starts is t = 10 min . The number of half-lives n that have passed is calculated as n = t T_ 1/2 = 10 2 = 5 . The amount of substance remaining N after n half-lives is given by the formula N = N₀ ( 1 2 )^n , where N₀ is the initial amount. Given N₀ = 80 g , we have N = 80 ( 1 2 )^5 . N = 80 1 32 = 80 32 = 2.5 g . Answer: 2.5 ~g