Thermodynamics: Change in specific enthelpy

In summary, thermodynamics is the study of energy and its transformations, and it is important for understanding energy usage in different systems. Specific enthalpy is the amount of energy per unit mass of a substance and is different from total enthalpy. The change in specific enthalpy is calculated by subtracting the initial specific enthalpy from the final specific enthalpy, and it is affected by temperature, pressure, composition, and type of process or reaction. The change in specific enthalpy can be negative if energy is removed from the system, and the direction of energy flow must be considered when analyzing it.
  • #1
t3rom
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Homework Statement



What is the change in specific enthalpy if saturated water vapor at 100 bar compresses to a pressure of 150 bar? The temperature is constant.

Homework Equations



None

The Attempt at a Solution



I used this equation to solve the problem: delta h = delta e + p * delta v
I found the value of delta e and delta v from steam tables. The answer I'm getting is 190049 kj/kg which is incorrect. Any help would be greatly appreciated, TIA!
 
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  • #2
I got it. Had to lookup values of enthalpy at 100 bar and 150 bar then take the difference of them.
 

FAQ: Thermodynamics: Change in specific enthelpy

What is thermodynamics and why is it important?

Thermodynamics is the study of energy and its transformations. It is important because it helps us understand how energy is used and transferred in various systems, such as engines, power plants, and chemical reactions.

What is specific enthalpy and how is it different from enthalpy?

Specific enthalpy is the amount of energy per unit mass of a substance. It is different from enthalpy, which is the total energy of a substance. Specific enthalpy takes into account the mass of the substance, making it a more useful measure for analyzing processes and reactions.

How is the change in specific enthalpy calculated?

The change in specific enthalpy is calculated by subtracting the initial specific enthalpy from the final specific enthalpy. This change represents the energy added or removed from the system.

What factors affect the change in specific enthalpy?

The change in specific enthalpy is affected by the temperature, pressure, and composition of the substance. It is also influenced by the type of process or reaction occurring, such as heating, cooling, or phase change.

Can the change in specific enthalpy be negative?

Yes, the change in specific enthalpy can be negative if energy is removed from the system. This could occur in a cooling process or during a phase change. It is important to consider the direction of energy flow when analyzing the change in specific enthalpy.

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