Answer:
As far as i know there are only three types of waves: transverse waves, longitudinal waves, and surface waves. Though maybe I'm incorrect.
A is Ea, which stands for activating energy. Energy is needed to get the reaction underway and Ea is the energy needed to “start” the reaction.
B is the temperature either released or absorbed.
The diagram shows that the reaction is exothermic based on the fact that the products energy is lower than the reactants. That is because energy (which is temperature in this case) is released during the process. If the reactants would have been lower than the products, the reaction would be endothermic.
A good first step is writing the amount in terms of ml.
19.2 gallons = 72.68 L = 72680 ml
that would mean it weighs 0.749*720680g = 54437.32ml = 54.437 L
hope that helps :)