Thallium-207 decays exponentially with a half life of 4.5 minutes. if the initial amount of the isotope was 28 grams, how many grams of the isotope will remain after 7 minutes?

Option B

Step-by-step explanation:

Thallium-207 decays exponentially with a half life period = 4.5 minutes.

So the explicit formula of exponential decay can be written as

=

= Amount after decay

= initial amount

n = decay constant

t = time for decay

Since half life of Thallium is 4.5 minutes.

So   =

ln = ln

-0.69314 = -4.5n ln e

4.5 n = = 0.154

Now we have to calculate amount remaining after 7 minutes when initial amount taken is 28 grams from the formula

=

=

grams

Option B is the answer.

Answer : B. 9.53 grams

Thallium-207 decays exponentially with a half life of 4.5 minutes. if the initial amount of the isotope was 28 grams,

The formula for half life is

Final value = initial value (1/2)^(Time /t(half life))

initial amount of the isotope = 28 grams

half life = 4.5 minutes

Time = 7 minutes

Plug in all the values

Final value

A = 28 * 0.34020= 9.52553

9.53 grams of the isotope will remain after 7 minutes

$9.41

step-by-step explanation:

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.