Download Tutorial V

Tutorial V(Thermodynamics)
(CYL110/CY110N)
Q1. Show that the free energy of mixing of three gases has a minimium value with
respect to each gas only when x1 = x2 = x3 = 1/3.
Q2. 2 dm3 of methane under 4 bar and 298 K and 4 dm3 of oxygen under 20 bar and 298
K are forced into a 3 dm3 evacuated reaction vessel, the temperature being maintained at
298 K. Calculate the change in entropy of gases assuming they are ideal ?
Q3. If 1.588 g of nitrogen tetraoxide gives a total pressure of 1.0133 bar when partially
dissociated into a 500-cm3 glass vessel at 25 °C, what is the extent of reaction? What is
the value of K? What is the extent of reaction at a total pressure of 0.5 bar?
Q4. As an illustration of the effect of initial composition, pressure, and the addition of an
inert gas, consider the equilibrium for the production of methanol from CO and H2:
CO (g) + 2H2 (g) ==== CH3OH (g)
The value of K at 500 K is 6.23*10-3. (a) A gas stream containing equimolar amounts of
CO and H2 is passed over a catalyst at 1 bar. What is the extent of reaction at equilibrium
? (b) To attain more complete reaction, the pressure is raised to 100 bar and 2 mole of
hydrogen is used per mole of CO. What is the equilibrium extent of reaction at 100 bar?
Q 5. What is the value of the equilibrium constant Kc for the dissociation of ethane into
methyl radicals at 1000 K?
∆ f G 0 ( CH 3 ) = 159 .82 kJmol
-1
and ∆ f G 0 ( C 2 H 6 ) = 109 .55 kJmol
-1
Q4. At 1393 K
Fe 2 O3 ( s ) + 3 CO (g) = 2Fe(s) + 3CO 2 ( g )
K = 0.0467
2CO 2 ( g ) = 2CO (g) + O 2 ( g )
K = 1.4 * 10 -12
What is the equilibrium pressure of O2 (g) in a vessel containing Fe2O3 (s) and Fe(s)
at equilibrium at 1393 K?
Q6. The measured density of an equilibrium mixture of N2O4 and NO2 at 15 °C and 1.103
bar is 3.62 g L-1, and the density at 75 °C and 1.013 bar is 1.84 g L-1. What is the enthalpy
change of the reaction N2O4 (g) = 2NO2 (g) ?