UNIVERSITY OF DAR ES SALAAM
CH 201: CHEMICAL THERMODYNAMICS
TUTORIAL-01
1. The change in the Gibbs energy of a certain constant-pressure process is found to fit the
expression ΔG/J = −85.40 + 36.5(T/K). Use the Gibbs–Helmholtz equation to calculate
the value of ΔH for the process.
2. Estimate the change in the Gibbs energy of 1.0 dm 3 of liquid octane when the pressure
acting on it is increased from 1.0 atm to 100 atm. Given that the mass density of octane is
0.703 g cm−3, determine the change in the molar Gibbs energy.
3. By integrating the Gibbs–Helmholtz equation between temperature T 1 and T2, and with
the assumption that ΔH is independent of temperature, show that
(
where
)
is the change in Gibbs energy at temperature T.
4. A container is divided into two equal compartments. One contains 3.0 mol H 2(g) at 25
°C; the other contains 1.0 mol N2(g) at 25 °C. Calculate the Gibbs energy of mixing when
the partition is removed. Assume that the gases are perfect.
5. The experimental values of the partial molar volume of K2SO4(aq) at 298 K are found to
fit the expression
where
(
=
⁄
(cm3 mol−1) and
is the numerical value of the molality of
. Use the Gibbs–Duhem equation to derive an equation for the molar volume
of water in the solution. The molar volume of pure water at 298 K is 18.079 cm 3 mol−1.
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