An object gains 10 joules of potential energy as it is lifted vertically 2.0 m. If a second object with one-half the mass is lifted vertically 2.0m, the potential energy gained by the second object will be a. 10j
b. 20j
c. 5.0j
d. 2.5j

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.