Half-life of a Reaction — Prelims Questions

A first-order reaction has a rate constant $k = 5.5 \times 10^{-14},\text{s}^{-1}$. Calculate the half-life of this reaction.

For a zero-order reaction, if the initial concentration of the reactant is doubled, how does its half-life change?

A radioactive isotope has a half-life of 10 days. If you start with 80 grams of the isotope, how much will remain after 30 days?

A second-order reaction has a rate constant $k = 0.05\,\text{L mol}^{-1}\text{s}^{-1}$. If the initial concentration of the reactant is $0.2\,\text{M}$, what is its half-life?

Which of the following statements about the half-life of a reaction is INCORRECT?

A reaction is found to have a half-life of 20 minutes when the initial concentration is $0.5\,\text{M}$. When the initial concentration is increased to $1.0\,\text{M}$, the half-life becomes 10 minutes. What is the order of the reaction?