Question

Please answer true or false and explain why for each of them. Thank you

1. Mark with T (True) or F (False) (2 points each) • Joule Thompson experiment corresponds to process with constant enthalpy. . The state functions (U.H,G,A) act as thermodynamic potentials when represented as functions of their natural variables. • The Gibbs free energy is equal to the maximum PV work done by the system on the envi- ronment. . The standard enthalpy of formation for any pure element in its reference state is temperature dependent The phase of an isolated single component system at fixed values of temperature and volume is defined by the lowest value of chemical potential • A spontaneous process maximizes the Gibbs free energy when temperature and pressure are held constant. • The temperature derivative of the chemical potential is discontinuous for a single component system undergoing a phase transition of the first kind. • The change in the internal energy of mixing for a real gas must be 0, if the process is done isothermally. • The temperature of a phase transition generally depends on pressure. • There are no conditions at which a two-component system will have 4 of its phases in equi- librium with each other. . When A moles of a liquid substance with partial molar volume V is added to a large amount of solvent the total volume of the mixture is generally increased by AV = nAVA The chemical potentials of the components in a mixture define how the internal energy changes upon changing the composition of the system at constant volume and entropy. • The change in entropy of a closed system is the same for every process between two specified equilibrium states • A closed system can experience a decrease in entropy only when there is heat transfer from the system to its surroundings during the process • Partial volume is an extensive property.

Answer 1

Solution:

1) True

Joule-thomson effect is isenthalpic process.

H1 = H2

2) True

The four state functions H,G,A and U are works as thermodynamic potentials.

3) False

Maximum work done is represented by Helmholtz free energy change.

ΔA = - PΔV

4) True

The standard enthalpy is represented at 25 °C temperature, its value changes with temperature.

5) False

Chemical potential is lowest at constant temperature and pressure.

6) False

Spontaneous processes minimizes free energy change.

7) False

First derivative of chemical potential is continuous.