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## Situation: Find the substance’s half-life, in days. • Round your answer to the nearest tenth. A 25 gram sample of a substa

Question

Situation:

Find the substance’s half-life, in days.

• Round your answer to the nearest tenth.

A 25 gram sample of a substance that’s

used for drug research has a k-value of

0.1229.

Enter the correct answer.

N = Noe

-kt

DONE

No = initial mass (at time t = 0)

?

N = mass at time t

k = a positive constant that depends on

the substance itself and on the units

used to measure time

t = time, in days

in progress
0

Mathematics
3 years
2021-07-23T18:50:07+00:00
2021-07-23T18:50:07+00:00 1 Answers
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0
## Answers ( )

Answer:

5.6 days

Step-by-step explanation:

We are given;

Initial Mass; N_o = 25 g

Mass at time(t); N_t = 25/2 = 12.5 (I divide by 2 because we are dealing with half life)

k = 0.1229

Formula is given as;

N_t = N_o•e^(-kt)

Plugging in the relevant values;

12.5 = 25 × e^(-0.1229t)

e^(-0.1229t) = 12.5/25

e^(-0.1229t) = 0.5

(-0.1229t) = In 0.5

-0.1229t = -0.6931

t = -0.6931/-0.1229

t = 5.6 days