Final answer:
Shamar is incorrect; in a first-order reaction, each half-life decreases the reactant concentration by half, not a constant mass.
Step-by-step explanation:
Shamar is incorrect in stating that in a first-order reaction the same mass of reactant is lost after each half-life. While the half-life of a first-order reaction is a constant and each successive half-life is the same length of time, the amount of reactant that remains after each half-life is always half of what was present at the start of that half-life period.
For a first-order reaction, the concentration of the reactant decreases by half with each half-life, meaning that it follows an exponential decay pattern. Therefore, the actual mass of the reactant that is lost after each half-life is not a constant amount, but it is a constant fraction (1/2) of the concentration that was present at the beginning of that half-life period.
This concept can be illustrated with the formula t1/2 = 0.693/k, which relates the half-life of a first-order reaction to its rate constant. Additionally, the relationship shows that the half-life is independent of the initial concentration of the reactants.