$A$ first order reaction has a rate constant of $1.5 \times 10^{-3} \ s^{-1}$. How long will $5.0 \ g$ of this reactant take to reduce to $3.0 \ g$?

What is the half-life of a first-order reaction if the time required to decrease the concentration of the reactant from $0.8 \ mol \ dm^{-3}$ to $0.2 \ mol \ dm^{-3}$ is $12 \ hour$ (in $hour$)?

Half-life period of a first-order reaction is $10 \ min$. Starting with an initial concentration of $12 \ M$,the rate after $20 \ min$ is:

In a first-order reaction $A \rightarrow B,$ if $k$ is the rate constant and the initial concentration of the reactant $A$ is $0.5 \ M,$ then the half-life is:

The rate constant for a first-order reaction is $0.02232 \ min^{-1}$. Calculate the time required for $75 \%$ completion of the reaction. (in $min$)

What is the time required for $99 \%$ completion of a first order reaction if the rate constant is $23.03 \ min^{-1}$?