For 1.4 mole of the radioactive isotope molybdenum-99, half-life = 67 hours,?

Posted by admin
Angelika asked:


how many disintegrations have occured after 15 minutes?

Plasma Vs LCD

This entry was posted on Monday, June 16th, 2008 at 6:10 am and is filed under Chemistry. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

« is anyone farmiliar with molybdenum as a motorcross oil additive?
Project with Molybdenum or Tungsten? »

2 Responses to “For 1.4 mole of the radioactive isotope molybdenum-99, half-life = 67 hours,?”

  1. alexander Says:
    June 16th, 2008 at 1:14 pm

    IF a half life occurs every 67 hours then 0.00373134328358208955223880597014925
    per 15 minutes.
    if a half life occurs every 15 minutes then it would be
    268 disintegrations in 67 hours.

  2. Liv Says:
    June 19th, 2008 at 3:48 am

    67 hours = 4020 minutes
    15 minutes = 0.25 hours

    ln 2 / 67 hrs = 0.0103/hr

    N(.283) = 1.4 x e^ (-.0103 x .25)
    = 1.4 x .9974
    = 1.3964 moles remaining

    1.4 mol - 1.3964 mol = 0.0036 moles

    .0036 x (6.02e23) = 2.167e21

    (or for sig figs, try 2.17e21)

Leave a Reply