ECH 3129
CHEMICAL ENGINEERING THERMODYNAMICS
TUTORIAL 1
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1.
(a) What is molar volume and how is it related to temperature?
(b) What is the ideal gas state?
(c) What is the equation of state? What is the general form of EOS?
(d) What is Pitzer correlation?
(e) What is compressibility factor, Z and how does it identify with intermolecular forces?
2. Sketch the PVT diagram and label all the necessary information.
3. Consider 7 kilograms of liquid carbon tetrachloride undergo a mechanically reversible, isobaric change
of state at 1 bar during which the temperature changes from 0°C to 20°C. The properties of liquid
carbon tetrachloride at 1 bar and 0°C may be assumed independent of temperature: β = 1.2 ×
10−3 K−1, CP = 0.84 kJ·kg−1·K−1, and ρ = 1590 kg·m−3. Determine ΔVt, W, Q, ΔHt, and ΔUt.
4. Compute the final pressure when the substance is heated from 15°C and 1 bar to 25°C at constant
volume. The table given below provides the specific volume, isothermal compressibility, and volume
expansivity of ethanol at 20°C and 1 bar, where β and κ may be assumed constant.
5. Consider ethylene at 25°C and at 14 bar. Calculate Z and V for the given condition using the following
equations.
(a) Truncated 3-term virial equation
(b) Generalized correlation.
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6. A garden hose with the water valve shut and the nozzle closed sits in the sun, full of liquid water. Initially,
the water is at 10°C and 6 bar. After some time, the temperature of the water rises to 40°C. Owing to the
increase in temperature and pressure and the elasticity of the hose, the internal diameter of the hose
increases by 0.37%. Estimate the final pressure of the water in the hose.
Data: β(ave) = 250 × 10−6 K−1 and κ(ave) = 45 × 10−6 bar−1
7. Storage is required for 35,000 kg of propane, which is received as a gas at 10°C and 1 atm. Two
proposals have been made:
(a) Store it as a gas at 10°C and 1 atm (Use RK’s equation).
(b) Store it as a liquid in equilibrium with its vapor at 10°C and 6.294 atm. For this mode of
storage, 90% of the tank volume is occupied by liquid (Use Rackett’s equation).
Which proposal is reasonable?
8. By using RK EoS, determine a good estimate for the compressibility factor Z of saturated hydrogen
vapor at 25 K and 3.213 bar. For comparison, an experimental value is Z = 0.7757. For data, use the
characteristic properties of the pure species table.
9. Estimate the density of liquid ethanol at 180°C and 200 bar. The characteristic properties of ethanol are
given in the following table:
10. Calculate compressibility (Z) and the molar volume (V) for boron trichloride for the following condition.
(For boron trichloride, Tc = 452 K, Pc = 38.7 bar, and ω = 0.086.)
(a) Using a generalized correlation for gases
(b) Redlich/Kwong equation
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