In the reaction H, H+H, there is an average energy change of 436 kJ/mol. This is an
(endothermic/exothermic) reaction
which means that energy is being
(absorbed/released) during the
overall reaction.

yes, water is wet, just as it makes other things wet, it is wet itself, kinda like ice, when ice is in water, the ice makes water cold, and ice is cold, therefore with that example, water is wet

the temperature of the gas, in k, not celsius.

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )