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Tatiana [17]
3 years ago
15

Assume that you have developed a tracer with first-order kinetics and k = 0.1 s − 1 . For any given mass, how long will it take

the tracer concentration to drop by (a) 50% and (b) by 75%?
Chemistry
1 answer:
anygoal [31]3 years ago
5 0

Answer: It will take 6.93 sec for tracer concentration to drop by 50% and 13.9 sec for tracer concentration to drop by 75%

Explanation:

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  =0.1s^{-1}

t = age of sample  

a = let initial amount of the reactant  = 100 g

a - x = amount left after decay process  

a) for tracer concentration to drop by 50%

a - x = amount left after decay process   = 50

t=\frac{2.303}{k}\log\frac{100}{50}

t=\frac{0.693}{0.1}

t=6.93sec

It will take 6.93 sec for tracer concentration to drop by 50%

b) for  tracer concentration to drop by 75 %

a - x = amount left after decay process   = 25

t=\frac{2.303}{k}\log\frac{100}{100-75}

t=\frac{2.303}{0.1}\times \log\frac{100}{25}

t=13.9sec

It will take 13.9 sec for tracer concentration to drop by 75%.

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