Question

Half-life equation for first-order reactions:
t1/2=0.693k
where t1/2 is the half-life in seconds (s), and k is the rate constant in inverse seconds (s−1).

a) What is the half-life of a first-order reaction with a rate constant of 4.80×10^−4 s−1?

b) What is the rate constant of a first-order reaction that takes 188 seconds for the reactant concentration to drop to half of its initial value?

Express your answer with the appropriate units.

c)A certain first-order reaction has a rate constant of 7.90×10^−3 s−1. How long will it take for the reactant concentration to drop to 18 of its initial value?

Express your answer with the appropriate units.