Comments on: For 1.3 mole of molybdenum-99, half-life 67 hours, how many disintegrations occured after 20 mins?

Comments on: For 1.3 mole of molybdenum-99, half-life 67 hours, how many disintegrations occured after 20 mins? http://molybdenuminfo.com/2008/06/10/for-13-mole-of-molybdenum-99-half-life-67-hours-how-many-disintegrations-occured-after-20-mins/ Answering your molybdenum questions Fri, 10 Sep 2010 23:03:56 +0000 http://wordpress.org/?v=2.6.3 By: sarge_247 http://molybdenuminfo.com/2008/06/10/for-13-mole-of-molybdenum-99-half-life-67-hours-how-many-disintegrations-occured-after-20-mins/#comment-63 sarge_247 Fri, 13 Jun 2008 00:30:37 +0000 http://molybdenuminfo.com/?p=76#comment-63 A(t)=(1.3)(1-R)^t 67 hrs=4020 min .65=1.3(1-R)^4020 .5=(1-R)^4020 R=1.724E-4 A(20)=1.3(1-1.724E-4)^20 A(20)=1.2955 mol= 7.799E23 1.3*6.02E23=7.826E23 7.826E23-7.799E23=2.7E21 atoms that disintegrate in 20 min A(t)=(1.3)(1-R)^t
67 hrs=4020 min
.65=1.3(1-R)^4020
.5=(1-R)^4020
R=1.724E-4

A(20)=1.3(1-1.724E-4)^20
A(20)=1.2955 mol= 7.799E23

1.3*6.02E23=7.826E23

7.826E23-7.799E23=2.7E21 atoms that disintegrate in 20 min

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