For 1.3 mole of molybdenum-99, half-life 67 hours, how many disintegrations occured after 20 mins?
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trish asked:
For 1.3 mole of the radioactive isotope molybdenum-99, half-life = 67 hours, how many disintegrations have occurred after 20 minutes?
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For 1.3 mole of the radioactive isotope molybdenum-99, half-life = 67 hours, how many disintegrations have occurred after 20 minutes?
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June 13th, 2008 at 12:30 am
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