Posted by **TlP** on Monday, May 12, 2014 at 6:26pm.

Suppose a patient is given 140mg of I−131, a beta emitter with a half-life of 8.0 days.

Assuming that none of the I−131 is eliminated from the person's body in the first 4.0 hours of treatment, what is the exposure (in Ci) during those first four hours?

Express your answer using two significant figures.

- Chemistry -
**DrBob222**, Monday, May 12, 2014 at 7:18pm
k = 0.693/t_{1/2}

k = approx 0.09 but you should get a more accurate number.

Convert 140 mg to number of atoms initially (at time = 0)

Use ln(No/N) = kt to determine N = number of atoms after four hours.

The difference between initial and after 4 hours is atoms that decayed in 4 hours.

Then 3.7E10 decays per second = 1 Ci

- Chemistry -
**Tom1**, Monday, May 12, 2014 at 7:51pm
that is wrong Ci does not equal 1

- To Tom1---Chemistry -
**DrBob222**, Monday, May 12, 2014 at 8:57pm
Read what I wrote. I said 3.7E10 dps = 1 Ci, not that Ci = 1.

## Answer This Question

## Related Questions

- Chemistry - Suppose a patient is given 140mg of I−131, a beta emitter ...
- Chemistry - Suppose a patient is given 140mg of I−131, a beta emitter ...
- chemistry - The disintegration of a radioisotope, such as I-131 to Xe-131, is ...
- chemistry - The disintegration of a radioisotope, such as I-131 to Xe-131, is ...
- chemistry - Iodine-131, a beta emitter, has a half-life of 8 days.How many grams...
- Exponential Growth and Decay - Doctors use iodine-131 to treat some forms of ...
- Math - Please show me how to solve: Doctors can use radioactive iodine to treat ...
- chemistry - Iodine-131 is used to destroy thyroid tissue in the treatment of an ...
- chemistry - The half-life of I-131 is 8.00 days. If a medical treatment involves...
- Chemistry - 2. The half-life of a radioactive element is important when ...

More Related Questions