Answer to Question #151250 in Organic Chemistry for Carolyn Walsh

Question

A sample of radioactive material has a half life of 30 minutes. how long will it take for 80 grams of that material to decay to 5 grams?

Answer 1

This is just an analytical question,

You solve it this way;

Half life = 30 minutes, this means for half the mass to decay, it takes 30 minutes.

80 ---> 40 (30 minutes)

40 ---> 20 (30 minutes)

20 ---> 10 (30 minutes)

10 ---> 5 (30 minutes)

Then add the time to get the total amount it takes to decay from 80g to 5g

= 30 + 30 + 30 + 30 minutes = 120 minutes = 2 hours.

Therefore it takes 2 hours for the radioactive material to decay to 5g.