# Science chemistry

posted by .

It takes 1 hour and 17 min. for a 1.000gsample of a certain isotope to decay to 0.121g. What is the half-life of this isotope? plssss helpp

• Science chemistry -

if n is the number of half-lives

(1/2)^n * 1.000 = 0.121

(1/2)^n = 0.121/1.000

n [log(1/2)] = log(0.121)

n = [log(0.121)] / [log(1/2)]

half life = [1h17m] / n

## Similar Questions

1. ### Physics check

A certain radioactive isotope has a half-life of one hour. At noon, 100g of the material is present. How much of the original isotope will be present at 3:00 p.m.----1/8 6:00 p.m.-----1/16 10:00 p.m.-----1/32 Are these correct?
2. ### Chemistry

Gallium65, a radioactive isotope of gallium, decays by first order-kinetics. The half-life of this isotope is 15.2 min. How long would it take for 7/8 of a sample of this isotope to decay?
3. ### college

a certain radioactive isotope has a half life or 850 years.how many years would it take for a given amount of this isotope to decay to 70% of that amount?
4. ### chemistry

It takes 1 hour and 17 min. for a 1.000g sample of a certain isotope to decay to 0.121g. What is the half-life of this isotope?
5. ### Chem

The decay constant for a radioactive isotope is 7.82 x 10-6 /y. What is the half-life of this isotope in years?
6. ### Calculus

My teacher wants me to use this formula for half life question C(t) = Ce^-kt but i used a different formula plz help. the question is: A radioactive isotope has a half life of 30 years. If we started off with 10 mg of this isotope …
7. ### chemistry

isotope A require 12h for its decay rate to fall to 1/64 of its intial value . isotope B has half-life = 1.5 half life of A how long does it take for decay rate of B fall to 1/32 of its initial value ?
8. ### Chemistry

If it takes 45 days for 80.0 mg of a particular radioactive isotope to decay to 10.0 mg what is its half-life?
9. ### Chemistry

If it takes 45 days for 80.0 mg of a particular radioactive isotope to decay to 10.0 mg what is its half-life?
10. ### Calculus

The rate of decay is proportional to the mass for radioactive material. For a certain radioactive isotope, this rate of decay is given by the differential equation dm/dt = -.022m, where m is the mass of the isotope in mg and t is the …

More Similar Questions