Final answer:
About 69.7 g of P32 was present 3.00 days ago before decaying to the current 62.7 g, calculated using the radioactive decay formula with a half-life of 14.3 days.
Step-by-step explanation:
To find out how much P32 was present 3.00 days ago, we can use the half-life formula for radioactive decay. The half-life of P32 is 14.3 days. The amount of radioactive isotope remaining can be calculated by the following equation:
N = N0 * (1/2)^(t/T)
Where:
t is the elapsed time,
Given that t = 3.00 days and T = 14.3 days and currently, there is 62.7 g of P32, we want to find out N0. Rearranging the formula to solve for N0, we get:
N0 = N / (1/2)^(t/T)
Replacing the known values:
N0 = 62.7 g / (1/2)^(3/14.3)
Now, using a calculator to find the results:
N0 = 62.7 g / (1/2)^(0.20979)
N0 = 62.7 g / 0.8992
N0 ≈ 69.7 g (rounded to two decimal places)
Therefore, about 69.7 g of P32 was present 3.00 days ago.