Thermodynamics

Manometer measure the pressure of a tank as 250 cm of Hg. For the density of Hg 13.6 × 10³ Kg/m³ and atmospheric pressure 101 KPa, calculate the tank pressure in MPa.

Which of the following state functions are extensive? (I) Pressure (P) (II) Temperature (T) (III) Enthalpy (H) 

1. II only 

2. II, III 

3. I, III 

4. I, II, III 

5. I only 

6. III only 

7. I, II 

8. None are true

Which of the following statements concerning the second and third laws of thermodynamics is/are true? (I) When the change in entropy of the system is equal in magnitude and opposite in sign to the change in entropy of the surroundings, the change in entropy of the universe is zero. (II) The change in entropy of the universe can be rewritten as −∆Gsytem/T. (III) In a perfect, pure crystal at absolute zero the entropy of the system is zero. 

1. III only 

2. II, III 

3. I only 

4. I, III

5. II only 

6. I, II, III 

7. I, II

Write short notes on State, point function and path function. 

What is the smallest temperature in degrees Fahrenheit you can have? Rankine?

A steam turbine inlet is at 1200 kPa, 500°C. The exit is at 200 kPa. What is the lowest possible exit temperature? Which efficiency does that correspond to?

Consider a hot-air heating system for a home. Examine the following systems for heat transfer. 

(a) The combustion chamber and combustion gas side of the heat transfer area. 

(b) The furnace as a whole, including the hot- and cold-air ducts and chimney. 

When a substance has completed a cycle v, u, h and s are unchanged. Did anything happen? Explain. 

Why are most of the compressed liquid or solid regions not included in the printed tables?

Determine the size of a spherical balloon filled with hydrogen at 30°C and atmospheric pressure for lifting 400Kg payload. Atmospheric air is at temperature of 27°C and barometer reading is 75cm of mercury.