# What is the change in molar Gibbs energy? What would be the change in molar Gibbs energy if the process occurred irreversibly?

Chemistry 340 Physical Chemistry for Biochemists

One mole of nitrogen is allowed to expand from 0.5 to 10 L. Calculate the change in entropy using the ideal gas law.

(a) Integrate the Gibbs-Helmholtz equation to obtain an expression for ∆G2 at temperature T2 in terms of ∆G1 at 1 T , assuming ∆H is independent of temperature.

(b) Obtain an expression for ∆G2 using the more accurate approximation that ∆ =∆ + − ∆ H H TT C 1 1 ( ) P where T1 is an arbitrary reference temperature.

When a liquid is compressed its Gibbs energy is increased. To a first approximation the increase in molar Gibbs energy can be calculated using (/) , GP V T ∂∂ = assuming a constant molar volume. What is the change in the molar Gibbs energy for liquid water when it is compressed to 1000 bar?

An ideal gas is allowed to expand reversibly and isothermally (25 °C) from a pressure of 1 bar to a pressure of 0.1 bar. (a) What is the change in molar Gibbs energy? (b) What would be the change in molar Gibbs energy if the process occurred irreversibly?

Helium is compressed isothermally and reversibly at 100 °C from a pressure of 2 to 10 bar. Calculate (a) q per mole, (b) w per mole, (c) ∆G, (d) ∆A, (e) ∆H, (f) ∆U, and (g) ∆S , assuming helium is an ideal gas.

Toluene is vaporized at its boiling point, 111 °C. The heat of vaporization at this temperature is 1 361.9J g . − For the vaporization of toluene, calculate (a) w per mole, (b) q per mole, (c) ∆H, (d) ∆U, (e) ∆G, and (f) ∆S.

What is the change in molar Gibbs energy? What would be the change in molar Gibbs energy if the process occurred irreversibly?