Part A You are using a Geiger counter to measure the activity of a radioactive s

Question

Part A You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 23.7minutes , what is the half-life of this substance? Express your answer with the appropriate units.   t1/2 = SubmitHintsMy AnswersGive UpReview Part Part B An unknown radioactive substance has a half-life of 3.20hours . If 23.2g of the substance is currently present, what mass A0 was present 8.00 hours ago? Express your answer with the appropriate units.   A0 = SubmitHintsMy AnswersGive UpReview Part Part C Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 42.0% of an Am-241 sample to decay? Express your answer with the appropriate units. Part A You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 23.7minutes , what is the half-life of this substance? Express your answer with the appropriate units.   t1/2 = SubmitHintsMy AnswersGive UpReview Part Part A You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 23.7minutes , what is the half-life of this substance? Express your answer with the appropriate units.   t1/2 = SubmitHintsMy AnswersGive UpReview Part   t1/2 =   t1/2 = SubmitHintsMy AnswersGive UpReview Part Part B An unknown radioactive substance has a half-life of 3.20hours . If 23.2g of the substance is currently present, what mass A0 was present 8.00 hours ago? Express your answer with the appropriate units.   A0 = SubmitHintsMy AnswersGive UpReview Part Part B An unknown radioactive substance has a half-life of 3.20hours . If 23.2g of the substance is currently present, what mass A0 was present 8.00 hours ago? Express your answer with the appropriate units.   A0 = SubmitHintsMy AnswersGive UpReview Part   A0 =   A0 = SubmitHintsMy AnswersGive UpReview Part Part C Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 42.0% of an Am-241 sample to decay? Express your answer with the appropriate units. Part C Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 42.0% of an Am-241 sample to decay? Express your answer with the appropriate units.   t1/2 =

Explanation / Answer

partA

1) t1/2=0.693/k1

k1=2.303/t log( a/a-x)

k1=2.303/23.7 log(400/100)

k1=0.058min^-1

t1/2=0.693/0.058

=11.8 min

part-b

2)1/t1log(a/a-x1) = 1/t2 log(a/a-x2)

     1/3.2 log(23.2/11.6)   1/8 log(23.2/a-x2)

a-x2=4.06grams

3)part-c

1/t1log(a/a-x1) = 1/t2 log(a/a-x2)

1/432 loga/a/2=1/t2 log 100/(100-42)

t2=339.5 years

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