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15.9: Standard Pressure

  • Page ID
    49540
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    You will often find enthalpy changes indicated by Δ and called standard enthalpy changes. The superscript is added to indicate that the enthalpy change has occurred at the standard pressure of 1 bar (100 kPa or 0.9869 atm). Unless very high pressures are involved, ΔH changes very little with a change in pressure, and so we have ignored superscripts up to this point. However, two other properties of matter called the entropy, symbol S, and the free energy, symbol G, are discussed in other sections. These are quite sensitive to pressure, and the inclusion of this superscript is important. For reasons of consistency therefore we will indicate standard enthalpy changes as Δ from now on.


    This page titled 15.9: Standard Pressure is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Ed Vitz, John W. Moore, Justin Shorb, Xavier Prat-Resina, Tim Wendorff, & Adam Hahn.

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