Half life word problem

Question

The half-life of Palladium-100 is 4 days. After 12 days a sample of Palladium-100 has been reduced to a mass of 5 mg.

What was the initial mass (in mg) of the sample?

What is the mass 5 weeks after the start?

Answer 1

Hi Kenzie,

 

The half life of Palladium-100 (or anything for that matter) is 4 days just means that however many of them there are now half of them will be dead at the end of the forth day. By the end of the eightieth day half of the half that remained will be dead. that just means you are left with a quarter of what you started with. And so on and so forth. For every proceeding four days just divide by half what you had the day before and if you just keep dividing at the third division you will get your answer.

 

5*10-3 gm* (1/2)*(1/2)*(1/2)

 

hope this helps