Cesium-137 has a half life of 30 years. What percent of the radioactive cesium parent atoms will remain after 90 years?

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

i would say b

explanation:

but i think i would need more information than that

16

explanation:

the marks go by 4s