The spectrum of an excited gas is a series of discrete lines becausea. in multielectron atoms, each electron emits a certain, unique wavelength. b. different atoms in the gas have different ionization states. c. other wavelengths are absorbed by the gas. d. electrons exist in quantized energy states, and only certain transitions are possible

8.29 two streams containing pyridine and acetic acid at 25°c are mixed and fed into a heat exchanger. due to the heat-of-mixing effect, it is desired to reduce the temperature after mixing to 25°c using a stream of chilled ethylene glycol as indicated in the diagram. calculate the mass flow rate of ethylene glycol needed. the heat capacity of ethylene glycol at these conditions is approximately 2.8 kj/(kg k), and the enthalpy change of mixing (δmixh) is given below.