Final answer:
The question is about calculating the remaining mass of a Cs-137 sample after 28 years using the given decay rate. The topic involves radioactive decay and beta decay, common in high school Chemistry. An exact answer is not provided due to the lack of a necessary formula linking mass and decay rate.
Step-by-step explanation:
The subject of this question is Chemistry, specifically involving the concept of radioactive decay and its calculations in high school level studies. We are given that a sample of cesium-137 (Cs-137) with an initial mass of 76 mg decays according to a given rate function. The student is asked to calculate the remaining mass of the sample after 28 years using the given decay rate.
To solve this, we would integrate the rate function from 0 to 28 years, subtracting this from the initial mass to find the remaining amount. Alas, without the proper formula for decay that links the mass and decay rate, we cannot provide an answer. In the half-life examples provided, substances undergo beta decay, where an unstable nucleus emits a beta particle. However, for Cs-137, it primarily undergoes beta decay, releasing beta particles as it transforms into a stable isotope.