21. Nuclear Chemistry
Rate of Radioactive Decay
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ANSWERS OPTIONS
A
2.2%
B
0.45%
C
4.3%
D
0.15%
A 2.5 g sample of rock contains thorium and produces 46 dis/s. Calculate the percent by mass of 232Th in the rock if the half-life of 232Th is 1.405×1010 yr.