Question

An element with
mass 510 grams decays by 26.3% per minute. How much of the
element is remaining after 7 minutes, to the nearest 10th of a gram?

Answer 1

Answer:

60.2 grams is remaining after 7 minutes.

Step-by-step explanation:

Exponential equation for amount of substance:

The exponential equation for the amount of a substance is given by:

$A(t) = A(0)(1-r)^t$

In which A(0) is the initial amount and r is the decay rate, as a decimal, and t is the time measure.

An element with mass 510 grams decays by 26.3% per minute.

This means that $A(0) = 510, r = 0.263$

So

$A(t) = A(0)(1-r)^t$

$A(t) = 510(1-0.263)^t$

$A(t) = 510(0.737)^t$

How much of the element is remaining after 7 minutes?

This is A(7). So

$A(7) = 510(0.737)^7 = 60.2$

60.2 grams is remaining after 7 minutes.