Carbon-14 has a half-life of 5720 years and this is a first order reaction. if a piece of wood has converted 75% of the carbon-14, then how old is it? 11440 years1430 years4750 years2375 years4290 years

11440 years

Explanation:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

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

where,

k = rate constant  

t = age of sample  

a = let initial amount of the reactant  = 100

x = amount decayed = 75

a - x = amount left after decay process  = 100 - 75 = 25

Thus the piece of wood is 11440 years old.

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explanation: