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Chemical Engineering vocabulary · Thermodynamics and Physical Properties

Enthalpy

Meaning in chemical engineering, with examples

/ˈɛnθəlpi/nounCommon term

In chemical engineering, enthalpy means: A measure of the heat content of a substance, used to calculate how much energy is needed to heat, cool, vaporize or react it at constant pressure. Usually given in kJ/kg or kJ/mol.

In Turkish: entalpi, ısı içeriği

How it is used

Used in every energy balance and in steam tables. Engineers talk about stream enthalpy, enthalpy change (ΔH) and enthalpy of reaction. Only changes in enthalpy matter, so values are given relative to a reference state.

Example sentences

  1. Take the steam enthalpy from the steam tables at 10 bar.

  2. The enthalpy of reaction is −95 kJ/mol, so we have to remove a lot of heat.

Common collocations

  • enthalpy change
  • enthalpy of reaction
  • enthalpy of vaporization
  • specific enthalpy
  • energy balanceA calculation that tracks all the energy entering and leaving a system as heat, work and the enthalpy of the streams, so that heating and cooling needs can be found.
  • heat capacityThe amount of heat needed to raise the temperature of a material by one degree. Per kilogram it is called specific heat capacity; water's is about 4.18 kJ/(kg·K).
  • latent heatThe heat taken in or given out when a substance changes phase, for example from liquid to vapor, without any change in temperature.
  • exothermicDescribes a reaction or process that releases heat to its surroundings, such as combustion, neutralization or most polymerizations.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Thermodynamics and Physical Properties

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