H ALF L IFE P RACTICE. Y OU HAVE 5 G OF SODIUM 25. H OW MUCH WOULD YOU HAVE AFTER 3 HALF LIVES ?...
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Transcript of H ALF L IFE P RACTICE. Y OU HAVE 5 G OF SODIUM 25. H OW MUCH WOULD YOU HAVE AFTER 3 HALF LIVES ?...
HALF LIFE PRACTICE
YOU HAVE 5G OF SODIUM 25. HOW MUCH WOULD YOU HAVE AFTER 3 HALF LIVES?
Step 1:2512.56.256.25g remain
Now You
C14 HAS A HALF LIFE OF 5730 YEARS. IF YOU HAD 88G, HOW MUCH C14 WOULD REMAIN AFTER 5 HALF LIVES?
Step 1:884422115.52.75g
ACTINIUM 226 HAS A HALF LIFE OF 28 HOURS. 100 G OF ACTINIUM 226 DEGRADES OVER 56 HOURS. HOW MUCH WILL BE LEFT?
Step 1: 56/28=2Step 2: 100g50g25g
25g
Now You
AFTER 11,200 YEARS, A SAMPLE OF RADIUM-226 HAS DECAYED. IT HAS A HALF-LIFE OF 1600 YEARS. THE SAMPLE WAS ORIGINALLY 162 GRAMS. HOW MUCH IS LEFT?
Step 1: 11,200/1600=7Step 2:
1628140.520.2510.1255.0625 2.53125
2.53125g
THE HALF LIFE OF ISOTOPE X IS 2 YEARS. HOW LONG WOULD IT TAKE FOR 4G TO DECAY TO .5G?
Step 1: 421.5(3 Half lives have passed)Step 2:3X2years=6 years
NOW YOU
CARBON HAS A HALF LIFE OF 5730 YEARS. HOW LONG WOULD IT TAKE 100G TO DECAY TO 25 GRAMS?
Step 1:1005025 (2 half lives have passed)Step 2:5730 years X 2=11460 Years
A SAMPLE INITIALLY CONTAINS 60G OF THORIUM 234. AFTER 48 DAYS ONLY 7.5 GRAMS REMAIN. HOW LONG IS ONE HALF LIFE?
Step 1: 6030157.5 (3 half lives have passed)
Step2: 48/3=16
16 days
Now You
WE START WITH 500G OF ISOTOPE X. IN 10,000 YEARS WE END WITH 7.8G. HOW LING IS ONE HALF LIFE FOR ISOTOPE X?
Step 1: 50025012562.531.2515.67.8
(6 half lives have passed)Step 2: 10,000/6 = 1666.66
One half life is 1666.66 years