Question

You are performing an experiment that uses 114Ag. 113Ag is radioactive, decays by beta-- emission and has a half-life of 21 minutes. It requires 4.2 hours to ship the material from the warehouse to your laboratory. How many grams should you order if the experiment requires that you have 0.0575 grams to begin the experiment?

Answer 1

Answer: The 234.74 grams of sample should be ordered.

Explanation:

Let the gram of  114 Ag to ordered be $N_o$

The amount required for the beginning of experiment = 0.0575 g

Time requires to ship the sample = 4.2hour = 252 min(1 hr = 60 min)

Half life of the sample =${t_{\frac{1}{2}}$ = 21 min

$\lambda =\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{21 min}=0.033 min^{-1}$

$\log[N]=\log[N_o]-\frac{\lambda t}{2.303}$

$\log[0.0575 g]=\log[N_o]-\frac{0.033 min^{-1}\times 252 min}{2.303}$

$N_o=234.74 grams$

The 234.74 grams of sample should be ordered.