If the half life of sodium-24 is 15 hours, how much remains from an 8.0 g sample at the end of 60 hours?
a) 0.5g
b) 1.0 g
c) 4.0g
2007-06-06 13:43:52 · 3 answers · asked by Jill H 1 in Science & Mathematics ➔ Chemistry
Taking away 1/2 each half-life leaves .5 grams after 60 hours.
2007-06-06 13:46:52 · answer #1 · answered by science teacher 7 · 0⤊ 0⤋
0.5g
think of it as dividing the mass (grams) in half.
first you need to find out how much times you need to divide the mass by 2. (60/15 = 4)
8/2 = 4
4/2 = 2
2/2 = 1
1/2 = 0.5
you're done
2007-06-06 13:47:43 · answer #2 · answered by LITA = BEST *SAVE_US.Y2J* -ACW- 5 · 0⤊ 0⤋
60 hr is 4 half-lives;
8g x 1/2 x 1/2 x 1/2 x 1/2 = 0.5g
This might be a trick question; so check your text book to be sure
2007-06-06 13:50:55 · answer #3 · answered by Flying Dragon 7 · 0⤊ 0⤋