Transcript NUCLEAR

THIS SERIES OF REACTIONS IS A TRANSMUTATION SERIES, A SERIES OF NUCLEII
DECOMPOSE INTO ITHER SPECIES UNTILL A STABLE ISOTOPE IS PRODUCED TO END
THE PROCESS. A VARIETY OF RADIATION IS EMITTED.
QUESTIONS
#8- WHAT IS THE TIME (h) FOR POTASSIUM-42 TO UNDERGO THREE HALFLIFE PERIODS?
1
1ST T
1/2
2ND T
NUMBER OF HALF LIFE PERIODS = t/T
WHERE T = HALF LIFE (TABLE N)
t = TIME ELAPSED
1/4
3RD T
1/8
3 = t/ 12.4 h = 37.2h
#9 –If a sample of 10 grams decays to 5 grams after 2 days what is the half life?
1
1ST T
1/2
2ND T
1/4
3RD T
1/8
FRACTION REMAINING = REMAINING/ORIGINAL
5/10 = ½ REMAINING
It takes one half life to get to ½
the original. In this question that
is 2 days
#10- After 6 days what fraction of an element with a half life 2 days remains.
NUMBER OF HALF LIFE PERIODS = t/T
#T = t/T = 6/2 = 3
WHERE T = HALF LIFE (TABLE N)
t = TIME ELAPSED
1
1ST T
1/2
2ND T
1/4
3RD T
6 days is 3 half lives and 1/8 of
the sample remains,
1/8
#11- How many grams of I-131 will persist after 24 d if 40.0g was present initially.?
Fraction persist= (1/2)t/T = (1/2)24d/8.07d = 1/8
1/8 of 40 = 5g
40g
1ST T
20g
2ND T
10g
3RD T
5g