Which statement about reaction rates is true? (a)changing the temperature cannot speed up a reaction rate. (b)changing the amount of reactants will not change the reaction rate. (c)changing the surface area affects the reaction rate. (d)a catalyst slows down the reaction rate.

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.