Question

In: Other

Give 2 examples of how to determine a thermodynamic properties (H, S, G, etc) of a...

Give 2 examples of how to determine a thermodynamic properties (H, S, G, etc) of a substance by using the thermodynamic diagrams (PH Diagram, TS Diagram and Mollier Diagram).

Give 2 examples of how to determine a thermodynamic properties (H, S, G, etc) of a substance by using the tables of thermodynamic properties.

Each example must be different from each other

Solutions

Expert Solution

  • Thermodynamic properties like pressure, temperature, enthalpy, entropy and volume of a substance are represented using a single diagram called thermodynamic diagram.
  • The most common diagrams are Temperature-Entropy diagram(T-S), pressure-Enthalpy(P-H) diagram and Enthalpy-Entropy diagram (Mollier's diagram).
  • These diagrams are drawn based on data of water but these can be applied to any substance.
  • example 1: Using a P-H diagram determine the enthalpy of refrigerant R12 when the evaporator temperature is -20 0C and 1.5bar pressure. The superheated temperature difference is 100C.
  • First, draw the indicated pressure line of 1.5 bar(0.15MPa) on P-H diagram of R12.
  • determine the temperature as -20+10= -10 0C. and plot the line(below the 0 lines). extend the right side to the pressure line. Mark the point as 1.
  • The enthalpy value corresponding to point 1 is the value of enthalpy at that temperature.
  • example 2:
  • Superheated steam at 4000C and 1bar pressure. find enthalpy and entropy.
  • Use molliers diagram. identify the 4000C isotherm line and 1bar isobar line. the intersection point is named as A.
  • To find enthalpy, draw a straight horizontal line towards the left diagonal enthalpy lines. the values at the intersection give the value of enthalpy.
  • Similarly from point A draw a vertical line towards the bottom entropy line. the intersection point gives the value of entropy at A.

Thermodynamic tables:

  • Thermodynamic properties are tabulated so that data can be obtained more accurately than from diagrams.
  • The values are given so close and for the values in between them need to be interpolated linearly.
  • These are of two types. They are Saturated steam tables and superheated steam tables.
  • Steam tables are used for obtaining values accurately almost for any substance.
  • Example 1:
  • Find liquid enthalpy value and saturated vapor entropy value at 2270C
  • T H(kJ/kg) S(kJ/kg0C)
    226 971.5 6.239
    228 980.9 6.2249
  • use linear interpolation (y-y1)=(y2-y1)(x-x1)/(x2-x1)
  • then the value of enthalpy is H=976.5kJ/kg
  • the value of entropy is S=6.23195kJ/kg0C
  • Example 2
  • At 10kPa and 348.150C find enthalpy and entropy.
  • using the superheated steam table at the given temperature and pressure the enthalpy is 2640kJ/kg and entropy is 8.3168kJ/kg0C.

Note: please refer to the respective charts.


Related Solutions

Give 2 examples of how to determine a thermodynamic properties (H, S, G, etc) of a...
Give 2 examples of how to determine a thermodynamic properties (H, S, G, etc) of a substance by using the thermodynamic diagrams (PH Diagram, TS Diagram and Mollier Diagram). Give 2 examples of how to determine a thermodynamic properties (H, S, G, etc) of a substance by using the tables of thermodynamic properties. Each example must be different from each other
At a certain temperature, the Kp for the decomposition of H2S is 0.846. H​2​S(g) <---> ​H​2...
At a certain temperature, the Kp for the decomposition of H2S is 0.846. H​2​S(g) <---> ​H​2 (g) ​+ S (g)​   Initially, only H2S is present at a pressure of 0.161 atm in a closed container. What is the total pressure in the container at equilibrium? (in atm)
Based on the thermodynamic properties provided for water, determine the amount of energy needed for 269...
Based on the thermodynamic properties provided for water, determine the amount of energy needed for 269 g of water to go from 85.5 °C to 161 °C. Property Value Units Melting point 0.0 °C Boiling point 100.0 °C ΔHfusΔHfus 6.01 kJ/mol ΔHvapΔHvap 40.67 kJ/mol cp (s) 37.1 J/mol·°C cp (l) 75.3 J/mol·°C cp (g) 33.6 J/mol·°C
Based on the thermodynamic properties provided for water, determine the energy change when the temperature of...
Based on the thermodynamic properties provided for water, determine the energy change when the temperature of 1.45 kg of water decreased from 109 °C to 23.0 °C.
Based on the thermodynamic properties provided for water, determine the energy change when the temperature of...
Based on the thermodynamic properties provided for water, determine the energy change when the temperature of 0.750 kg of water decreased from 117 °C to 38.5 °C. Property Value Units Melting point 0 °C Boiling point 100.0 °C ΔHfus 6.01 kJ/mol ΔHvap 40.67 kJ/mol cp (s) 37.1 J/mol · °C cp (l) 75.3 J/mol · °C cp (g) 33.6 J/mol · °C
Based on the thermodynamic properties provided for water, determine the energy change when the temperature of...
Based on the thermodynamic properties provided for water, determine the energy change when the temperature of 0.750 kg of water decreased from 111 °C to 51.0 °C. Melting point 0 °C Boiling point 100.0 °C ΔHfus 6.01 kJ/mol ΔHvap 40.67 kJ/mol cp (s) 37.1 J/mol · °C cp (l) 75.3 J/mol · °C cp (g) 33.6 J/mol · °C
Fe2O3(s) + 3 CO(g) —> 2 Fe(s) + 3 CO2(g) delta H = ___ a. Calculate...
Fe2O3(s) + 3 CO(g) —> 2 Fe(s) + 3 CO2(g) delta H = ___ a. Calculate delta H for the reaction above using the following know thermochemical reactions 2Fe(s) + 3/2 O2(g) —> Fe2O3(s) delta h=-824.2 kJ CO(g) + 1/2 O2(g) —> CO2(g) delta h=-282.7. b. Is this reaction endothermic, exothermic, or both? How do you know?
Use the values found in Thermodynamic Properties to determine ΔS°, ΔH° and ΔG° at 298 K...
Use the values found in Thermodynamic Properties to determine ΔS°, ΔH° and ΔG° at 298 K for the reaction below. Enter all values to the 0.1 place. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) ΔS° ΔH° ΔG°
1. Determine the ROC for stability for transfer function H(s) = 1 / (s-2) ( s-1)...
1. Determine the ROC for stability for transfer function H(s) = 1 / (s-2) ( s-1) 2. Determine the ROC for stability for transfer function H(z) = (z-1) / (z+0.1) (z-0.2)
For the system with transfer function H(s)=1/(s-2)(s-1) determine the ROC for stability.
For the system with transfer function H(s)=1/(s-2)(s-1) determine the ROC for stability.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT