Question

The half-life of Au is 2.88*10^3s. What is the mass of a sample of 200/79 Au that has and activity of 1.42*10^12 Bq? It wants the answer in grams.

Answer 1

\[A=\lambda*N\]

\[\lambda=\frac{ 0.693 }{ 2.88*10^3 }\]

then you can figure out what the N is

then you should divided it with avogadro number. You get mole number then multiply it by Au molar mass.