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18 Nov 2019
All uranium is radioactive, and the major radioactive isotope-238 (^238 U) undergoes alpha-decay with a half-life of 4.5 Times 10^9 years while the isotope-235 (^235U) undergoes alpha-decay with a half-life of 0.7 Times 10^9 years. Calculate (a) the rate constant for decay of 23, U when time is expressed in years and (b) determine how many years it takes for the^235U/^238 U fraction to change from 1.65 to 0.0072. Show work and give correct number of significant figures and appropriate units:
All uranium is radioactive, and the major radioactive isotope-238 (^238 U) undergoes alpha-decay with a half-life of 4.5 Times 10^9 years while the isotope-235 (^235U) undergoes alpha-decay with a half-life of 0.7 Times 10^9 years. Calculate (a) the rate constant for decay of 23, U when time is expressed in years and (b) determine how many years it takes for the^235U/^238 U fraction to change from 1.65 to 0.0072. Show work and give correct number of significant figures and appropriate units:
Jean KeelingLv2
18 Nov 2019