Only 2.50 mg of zirconium-86 remains frrom a 40.0 -mg sample of zirconium-86 after 66 hours what is the 1/2?

Answer 1

The half-life is 16.5 hours. Here's why:

You started with 40 mg of the sample. After 16.5 hours, half of the sample decayed, and now 20 mg remains. After another 16.5 hours (33 hours total), only 10 mg of the sample remains. Another 16.5 hours later (49.5 hours total), only 5 mg remains. And, after another 16.5 hours (66 hours total), the sample is only 2.5 mg.

Answer 2

16.5 days is the half life-
A half life it the time required for a radio active element to lose half of its radation. so 1 half life of your element would be 20 mg, after the second half life, you would have 10mg, third halflife would be 5mg, and the fourth halflife would be 2.5mg.
Starting amount/2, Ans/2.... is how to determind halflife.
since your on your 4th halflife at 66 days,
66/4= 16.5 days. This means every 16.5 days, it losses half it radation, so at time of zero-40 mg, after 16.5 days, its has 20mg, at 31 days, 10mg
at 47.5 days, would have 5mg
at 66 days, 2.5
Hope that helps..

Answer 3

How many halvings do you need to get from 40.0 to 2.50? (It's a whole number,so you don't need to use the posh formula with logs in it).

Answer 4

16.5 hrs.