Question

Technetium has a half-life of six hours. If you obtain 100g of a pure technetium sample, after 18 hours how much of the pure substance will be remaining?

Answer 1

After 18 hours, the amount of pure technetium that will be remaining is 12.5 grams

Step-by-step explanation:

To solve the question, we note that the equation for half life is as follows;

`N(t) = N_0 ((1)/(2) )^{(t)/(t_(1/2))`

Where:

N(t) = Quantity of the remaining substance = Required quantity

N₀ = Initial radioactive substance quantity = 100 g

t = Time duration = 18 hours

`{t_(1/2)` = Half life of the radioactive substance = 6 hours

Therefore, plugging in the values, we have;

`N(t) = 100 ((1)/(2) )^{(18)/(6)} = 100 ((1)/(2) )^(3) = (100 )/(8) = 12.5 \ grams`

Therefore, after 18 hours, the amount of pure technetium that will be remaining = 12.5 grams.