Is 2- NO 2(g) -> N2O 4(g)-> 19 kcal classified as exothermic or endorthermic?

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.

Which statement best describes the flow of energy in this scenario

What does the field of thermodynamics relate to a-changes in nuclear reactions b- changes in energy in systems c changes in molecular structure d changes in atomic properties