The rate constant of a drug molecule has been given as 4.0 x 10⁻⁵/s. Calculate the half-life of the drug molecule. Show your work (2). A student was studying the decomposition of a drug molecules with time. The student plotted the values of [drug molecule, in M] vs [time, in s] and calculated the slope as -5.5 x 10⁻³. Based on this calculate the rate constant of this reaction and include the units in your answer.