During a reaction, the enthalpy of the reactants and the products are not equal. What does this result in? A. None of these
B. Absorption or release of energy
C. Change in chemical composition
D. Spin of electrons is reversed

How can a scientist assess whether a pure niobium (nb) sample is responsible for contaminating the lab with radioactivity? test the niobium sample to see whether it now contains other elements.test the niobium sample for the presence of niobium oxide compounds.heat the niobium, and see if the level of radioactivity in the lab increases.place the niobium under pressure, and see if the level of radioactivity in the lab increases.