Solution to Question 3%2c lecture 5

# Solution to - k = ln 2 t 1/2 = ln 2 5.30 y = 0.693/5.30 y = 0.131/y Use the integrated rate equation to obtain time t since you know k and N/N =

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Solution to Question # 3; lecture 5 How long will a 60 Co source be useful if it can be used until the γ-rays it produces reach 70 percent of the original intensity? 60 27 Co decays with a half–life of 5.30 years to produce 60 28 Ni. Convert given half-life (5.30 years) to rate constant k by using this equation:
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Unformatted text preview: k = ln 2 / t 1/2 = ln 2 / 5.30 y = 0.693/5.30 y = 0.131 /y Use the integrated rate equation to obtain time t since you know k and N /N ( = 100/70l; from question): ln (N/N o ) = - k t => ln (N /N) = kt => t = [ln (N /N)]/k = [ln (100/70)] / 0.131/y = 2.74 y...
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## This note was uploaded on 02/06/2012 for the course CHM 115 taught by Professor Towns during the Spring '08 term at Purdue University-West Lafayette.

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