For a first-order reaction, after 2.00 min, 20% of the reactants remain. Calculate the rate constant for the reaction. 1. 74.6 s−1 2. 0.00582 s−1 3. 0.000808 s−1 4. 0.00186 s−1 5. 0.013412 s−1

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.