Question

Sodium-24 has a hourly decay rate of about 5%.

How many grams of a 900 g sample will remain after 90 hours?

Round the answer to two decimal places.

Answer 1

The decay formula for a substance is given by N(t) = N0 * (1 - r/100)^t, where N0 is the initial amount of the substance, r is the hourly decay rate and t is the time in hours.

In this case, N0 = 900 g, r = 5% and t = 90 hours. Plugging these values into the formula gives us:

N(90) = 900 * (1 - 5/100)^90 ≈ 22.81 g

So after 90 hours, about 22.81 g of the original 900 g sample will remain.