At normal temperatures and pressures, hydrogen gas is composed of H2 molecules. An energy diagram for a hydrogen molecule appears in (Figure 1). Figure1 of 1 The figure shows energy as a function of position x. The position is measured from 0 to 0.3 nanometer on the x-axis. The energy is measured from 0 to 20 times 10 to the power of negative 19 joules on the y-axis. The graph decreases as a curve concave upward from approximately 0.04 nanometer and 20 joules to its minimum of 0 joules at approximately 0.08 nanometer. Then it increases basically as a curve concave downward to approximately 0.25 nanometer and 7 joules. At this point the graph is almost constant. Part A What energy photon is needed to dissociate a molecule of H2 ? Express your answer with the appropriate units.
