Question

The half-life of I-37 is 8.07 days. If 25 grams are left after 40.35 days, how many grams were in the original sample?

Answer 1

800 g

Step-by-step explanation:

We can express the decay of I-37 using the formula:

• Final Mass = Initial Mass *
  `0.5^{(Time)/(Half-Life) }`

We input the data:

• 25 g = Initial Mass *
  `0.5^{((40.35)/(8.07))}`

And solve for Initial Mass:

• 25 g = Initial Mass *
  `0.5^(5)`

• 25 g = Initial Mass * 0.03125

• Initial Mass = 800 g

Meaning that out 800 grams of I-37, only 25 will remain after 40.35 days.