Chemistry

It took 109.8 years for a 300.0 mg sample of an unknown radioactive material to completely disintegrate. Calculate the mass of the element (in grams/mole) assuming that the disintegrations per second are constant over the life-time of the sample, and the sample is labeled 100.0 Ci (Curie= 3.7x10^10 disintegrations per second)

This material has a half-life. It NEVER completely disintergrates.

That is what is written in the problem.

The assumptions here are wild.

OK. If all of the atoms are going to "disintegrate", and they do so at a "constant rate" independent of mass, then


Time= numberatoms/rate

The number of atoms= avagNumber*moles=
avagNumber*mass/molmass

and then you solve for molmass.

time= avagnumber*mass/molmass*rate

You are given time, avagnumber, mass, and rate. Make certain you have time and rate in consistent units.

  1. 👍 0
  2. 👎 0
  3. 👁 106
  1. 2345678p

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    The quantity Q of radioactive carbon remaining in a 300 - gram wood sample at time t is given by the expression Q(t) = 300 e^{- 0.000324*t}. How much radioactive carbon remains in the sample after (a) 200 years, (b) 50000 years,

    asked by Irina on March 19, 2015
  2. Math

    How do I solve this if there is no equation to this 1. The population of the bacteria in a Petri dish increases by a factor of 10 every 10 hour. If there are initally 20 bacteria in the dish, how long will it take before the

    asked by Jake on January 28, 2012
  3. College Algebra

    The half-life of a radioactive material is about 34.6 years. How much of a 1-gram sample of the material is left after 30 years?

    asked by Anonymous on October 20, 2012
  4. Science

    A material has 32 atoms in all; 24 decayed and the rest undecayed. If the half-life of the radioactive material is 1000 years, what is the age of the material? a. 1000 years b. 2000 years c. 3000 years d. 4000 years

    asked by Angie on April 15, 2009
  5. Algebra please check my answers

    1) The linear function f(x) contains the points (-10, -29) and (-2, 83). If g(x) = 25x - 50, which statement is true? A. The functions f(x) and g(x) both have positive slopes.

    asked by David on May 21, 2014
  6. Pre Calculus

    If a 25 mg sample of radioactive material decays to 18.4 mg in 5 years, how long will it take the sample to decay to 20.5 mg?

    asked by Brianna on November 20, 2014
  7. physics

    After 1.84 days, the activity of a sample of an unknown type radioactive material has decreased to 85.8% of the initial activity. What is the half-life of this material? (in days)

    asked by andrew on June 3, 2012
  8. Physical Science

    A gram of radioactive material has a half-life of one year. After four years how much radioactive material will be left...0g, 1/2g, or 1/4g? None of the above. The answer one-half to the fourth power.

    asked by Gina on March 29, 2007
  9. Science

    When Marie Curie Isolated uranium from pitchable, she realized that the [itchable was more radioactive than the uranium she had extracted. What did she conclude about her observations? pitchblende itself is a radioactive element

    asked by jeje on January 7, 2015
  10. Calculus-Modeling Equations

    An unknown radioactive element decays into non-radioactive substances. In 420 days the radioactivity of a sample decreases by 39 percent. 1.What is the half-life of the element? 2.How long will it take for a sample of 100 mg to

    asked by Kim on March 6, 2009

More Similar Questions