9.A quantity of oxygen gas had 16.32g of the radioactive isotope oxygen-19 in it. When measured exactly 10 minutes later, the amount of oxygen-19 was 0.964g. What is the half-life, in seconds, of oxygen-19? (3 marks
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fraction remainig, f was 0.964/16.32 after 6000 sec, so eqn. is
f = (0.964/16.32)^(t/600)
for half-life , 0.5 = (0.964/16.32)^(t/600)
t = 600*log 0.5 / log (0.964/16.32)
= 147 sec
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f = (0.964/16.32)^(t/600)
for half-life , 0.5 = (0.964/16.32)^(t/600)
t = 600*log 0.5 / log (0.964/16.32)
= 147 sec
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