Which of the following is not a physical property of matter?
a. ductility
b. color
c.thermal conductivity
d. reactivity with water

Part 1: it is a endothermic reaction because the potential energy level at the finishing point(point c) is higher than the potential energy level at the start of the reaction (point a).

Part II change in enthalpy/delta H = ending energy - beginning energy(if the result is positive, it is endothermic reaction. If it is negative, it is exothermic reaction). The highest point - starting energy = activation energy. Beginning potential energy - ending potential energy = change in enthalpy. It is all relative, not in absolute term when it comes to reactions.