Determine the time required for an original 24.0-gram sample of sr-94 to decay until only 1.5 grams of the sample remains unchanged.

Check explanation.

Explanation:

In this question, we are to calculate for the time required for an original mass of a sample to to decay to another mass of the sample.

We can alive this by using the equation below;

N(t) = N(o) × (1/2)^t/t-half life------------------------------------------------------------(1).

Where N(t/) is the amount left after time t, which is given as 1.5 gram from the question.

N(o) is the initial amount of the substance, this is given as 24 gram.

t-half life= half life if the decaying substance. We make an assumption that the Half life is 10 years.

t= is the time required for an original mass of a sample to to decay to another mass of the sample.

Therefore, 1.5 g/24 g= (1/2)^t/10 years.

=> 0.625 = (1/2)^t/10.

==> t/10 log 0.5 = log 0.625.

==> t = 6.781 years.

Check attached picture for the exclusive solution.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).

i think it's c. i'm not sure but i think so.