So, you can't add them unless you convert one to the other.

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SUMMARY

The discussion focuses on the relationship between pressure and energy units, specifically the conversion between kilopascals (KPa) and kilojoules per kilogram (KJ/kg). The equation Tds = dh - vdP is utilized to derive enthalpy, but the user encounters a challenge when attempting to add values in KPa and KJ/kg. It is established that these units cannot be directly combined due to their differing dimensions, as KPa represents pressure while KJ/kg represents energy per unit mass.

PREREQUISITES
  • Understanding of thermodynamic equations, specifically Tds relationships.
  • Familiarity with unit conversions in physics and engineering.
  • Knowledge of pressure and energy units, particularly KPa and KJ/kg.
  • Basic calculus skills for rearranging and integrating equations.
NEXT STEPS
  • Research the dimensional analysis of physical quantities to understand unit compatibility.
  • Study thermodynamic properties and their relationships, focusing on enthalpy calculations.
  • Learn about integrating thermodynamic equations for practical applications.
  • Explore conversion factors and methods for transforming pressure units to energy units.
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Students and professionals in thermodynamics, mechanical engineers, and anyone involved in energy calculations and unit conversions in physical sciences.

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Homework Statement



find ethalpy using Tds relationship

Homework Equations



Tds=dh-vdP

The Attempt at a Solution


i had to reaarange and integrate to solve for enthalpy. but now i need to add a number in KPa to a number in KJ/Kg, can i do this? How do i change KPa to KJ/Kg?
thanks
 
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You can't they don't match - unless there is a bit you are missing.

pressure = kg / (m·s^2)
energy = kg m^2 / s^2

KPa = kg m^1 s^-2
KJ/kg = kg m^2 s^-2 / kg = m^2 s^-2
 

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