SOLUTION: 1.Phosphorus-32 is used to study a plant's use of fertilizer. It has a half life of 14.3 days. Write the exponential decay function for a 50-mg sample. Find the amount of phosphoro

Question 136174: 1.Phosphorus-32 is used to study a plant's use of fertilizer. It has a half life of 14.3 days. Write the exponential decay function for a 50-mg sample. Find the amount of phosphorous- 32 remaining after 84 days?
2. Iodine-131 is used to find leaks in water pipes. It has a half life of 8.14 days. Write the exponential decay function for a 200-mg sample. Find the amount of iodine-131 remaining after 72 days.
Thank you for helping me kind tutors
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
The half-life decay formula:
:
A = Ao * 2^(-t/h)
Where:
A = resulting amount after t time
Ao = initial amount
t = elapsed time
h = half-life of the substance
:
1.Phosphorus-32 is used to study a plant's use of fertilizer. It has a half life of 14.3 days. Write the exponential decay function for a 50-mg sample. Find the amount of phosphorous- 32 remaining after 84 days?
:
A = 50 * 2^(-84/14.3)
:
A = 50 * 2^-5.874
:
A = 50 * .017; find 2^-5.874 on a good calculator
:
A = .8525 mg remain after 84 days
:
:
2. Iodine-131 is used to find leaks in water pipes. It has a half life of 8.14 days. Write the exponential decay function for a 200-mg sample. Find the amount of iodine-131 remaining after 72 day
:
Do this exactly the same way.
A = 200 * 2^(-72/8.14)
:
Do you have any questions?

RELATED QUESTIONS
The half-life of a radioactive substance is the time it takes for half of the material to (answered by ankor@dixie-net.com)

Iodine-131 is used to find leaks in water pipes. It has a half life of 8.14 days. Write... (answered by stanbon)

1. Arsenic-74 is used to locate brain tumors. It has a half-life of 17.5 days. Write an... (answered by jim_thompson5910)

Brand A fertilizer is 32% phosphorus and Brand B is 18% phosphorus. How much of each... (answered by richwmiller)

Use the exponential decay equation given below, where A is the amount of a radioactive... (answered by josgarithmetic)

Phosphorous-32 is used to mark cells in biological experiments. If phosphorous-32 has a... (answered by scott8148)

The half-life of a certain radioactive material is 32 days. An initial amount of the... (answered by ankor@dixie-net.com)

Iodine - 131 is a radioactive isotope used in medicine. Its half-life or decay rate of... (answered by ikleyn)

The half-life of a certain radioatcive material is 85 days. An initial amount of the... (answered by ankor@dixie-net.com)