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A sample of a radioactive substance has an initial mass of . This substance follows a continuous exponential decay model and has a half-life of minutes. (a)Let be the time (in minutes) since the start of the experiment, and let be the amount of the substance at time . Write a formula relating to . Use exact expressions to fill in the missing parts of the formula. Do not use approximations. (b)How much will be present in minutes? Do not round any intermediate computations, and round your answer to the nearest tenth.

User Xfx
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a. The formula relating y (the amount of the substance) to t (the time in minutes) can be expressed as:


y = y_o * e^(-kt)

b. The amount of the substance present in 6 minutes is approximately 16.2 mg.

How much will be present in minutes?

(a) The formula relating y (the amount of the substance) to t (the time in minutes) can be expressed as:


y = y_o * e^(-kt)

Where:

y₀ is the initial amount of the substance (27.1 mg in this case),

k is the decay constant (related to the half-life), and

t is the time in minutes.

To determine the value of k, use the relationship between the half-life (T½) and the decay constant (k):

T½ = ln(2) / k

Given that the half-life is 8 minutes, substitute this value into the equation and solve for k:

8 = ln(2) / k

Solving for k:

k = ln(2) / 8

Now substitute the values of y₀ and k back into the formula:

y = 27.1 *
e^(- (ln(2) / 8) * t)

(b) To find how much of the substance will be present in 6 minutes, substitute t = 6 into the formula:


y = 27.1 * e^(- (ln(2) / 8) * 6)\\y \approx 27.1 * e^(-0.08664 * 6)\\y \approx 27.1 * e^(-0.51984)

y ≈ 27.1 * 0.5959

y ≈ 16.18

By rounding to the nearest tenth, the amount of the substance present in 6 minutes is approximately 16.2 mg.

Complete question

A sample of a radioactive substance has an initial mass of 27.1 mg. This substance follows a continuous exponential decay model and has a half-life of 8 minutes. (a) Lett be the time in minutes) since the start of the experiment, and let y be the amount of the substance at time t. . Dino ? Write a formula relating y to t. Use exact expressions to fill in the missing parts of the formula. Do not use approximations. y = ---e^---t (b) How much will be present in 6 minutes? Do not round any intermediate computations, and round your answer to the nearest tenth.

User Elicohenator
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