tiffany2842
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The half-life of iodine-124 is 4 days. A technician measures a 40-mCi sample of iodine-124. How many half-lives of iodine-124 occur in 16 days? How much iodine-124 is in the sample 16 days after the technician measures the original sample?

Respuesta :

joseaaronlara

Answer:

The answer to your question is:

a) 4 half-life

b)  2.5 mCi

Step-by-step explanation:

Half-life of iodine 124 is 4 days

# of half- lives in 16 days = ?

Process

                           0 days -----------------  0 half-life

                           4 days ------------------ 1 half life

                           8 days ------------------  2 halves lives

                         12 days  -----------------   3 halves lives

                         16 days  -----------------   4 halves lives                            

b)                        40 mCi   ---------------- initially

                          20 mCi   ---------------- 1 half life

                          10 mCi    ----------------  2 half life

                           5 mCi    ----------------   3 half life

                         2.5 mCi   ----------------   4 half life

yhixd

Answer:

3 half-lives; 3.125 mCi

Step-by-step explanation:

A half-life of carbon-11 is 20min, so there are 60÷20=3half-lives in 1 hour.Let x=the number of half-livesin 1 hour, 3.Let y=the sample size after 1hour.Let a=the starting sample size,25 mCi.Let b=the decay factor orhalf-life, 0.5.y   ====a•bx25•0.5325•0  .  1253  .  125 A half life of carbon 11 is 20 minutes, so there are 60 divided by 20 equals 3 half lives in 1 hour. Let x equal the number of half lives in 1 hour, 3. Let y equal the sample size after 1 hour. Let a equal the starting sample size, 25 millicuries. Let b equal the decay factor or half life, 0.5. Y equals a multiplied by b raised to the power of x. Equals 25 multiplied by 0.5 cubed. Equals 25 multiplied by 0.125. Equals 3.125.

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