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andrew11 [14]
3 years ago
11

If a sample of C-14 initially contains 1.5 mmol of C-14, how many millimoles will be left after 2255 years?

Chemistry
1 answer:
CaHeK987 [17]3 years ago
8 0

Answer: 3.2\times 10^{-4} millimoles will be left after 2255 years.

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  

t = age of sample

a = let initial amount of the reactant  

a - x = amount left after decay process  

a)  t_{\frac{1}{2}} of carbon = 5730 years

k}=\frac{0.693}{5730}=1.21\times 10^{-4}years^{-1}

b) millimoles left after 2255 years

2255=\frac{2.303}{1.21\times 10^{-4}}\log\frac{1.5}{a-x}

\log\frac{1.5}{(a-x)}=8.44

\frac{1.5}{(a-x)}=4628.5

(a-x)=3.2\times 10^{-4}millimoles

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