One mole of ammonia gas is contained in a vessel which is capable of changing its volume (a compartment sealed by a piston, for example). the total energy u (in joules) of the ammonia is a function of the volume v (in cubic meters) of the container, and the temperature t (in degrees kelvin) of the gas. the differential du is given by du 840dv + 2732dt. (a) how does the energy change if the volume is held constant and the temperature is decreased slightly? a. it increases slightly. b. it does not change. c. it decreases slightly.(b) how does the energy change if the temperature is held constant and the volume is increased slightly? a. it increases slightly. b. it decreases slightly. c. it does not change(c) find the approximate change in energy if the gas is compressed by 350 cubic centimeters and heated by 4 degrees kelvin. change in