32P has a half life of 14.26 days. If you initially have 100.0g of 32P how many grams of it remain after 3 half life periods?
2007-07-20 15:57:15 · 4 answers · asked by AP 1 in Science & Mathematics ➔ Chemistry
Take half each time...
1st half-life... 50.0 grams
2nd half-life... 25.0 grams
3rd half-life... 12.5 grams
Now, remember... the isotope doesn't just disappear. It converts to the less radioactive isotope.
Hope this helps you.
2007-07-20 16:03:10 · answer #1 · answered by Anonymous · 0⤊ 0⤋
After 1 half life you would have 50 g. After 2 half lives you would have 25 g. After 3 half lives you would have 12.5 g
2007-07-20 23:04:37 · answer #2 · answered by drochem 5 · 0⤊ 0⤋
You can also use logarithms to solve related questions like this one.
Af = Ao(0.5)^(x/t)
Af= final amount
Ao = initial amount
x = # of periods ( in this case, 3)
t = period of each half life
Af = 100.0(0.5)^(42.78/14.26)
Or simply Af = 100.0(0.5)^3 since you know 3 half life periods have occured.
Af = 12.5g
2007-07-21 00:01:21 · answer #3 · answered by Anonymous · 0⤊ 0⤋
After the first half-life period, you have 0.5 left. After the second, you have 0.25. After the third, 0.125
100gP-32 x 0.125 = 12.5g P-32
2007-07-20 23:04:38 · answer #4 · answered by steve_geo1 7 · 0⤊ 0⤋