Standard / Formation / Reaction

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madisondesilva1c
Posts: 91
Joined: Fri Sep 28, 2018 12:16 am

Standard / Formation / Reaction

Postby madisondesilva1c » Mon Feb 04, 2019 10:17 am

Is there a way to know when to use each enthalpy value, if so can someone please summarize them? I know that one must use the standard enthalpy when solving for the enthalpy of the reaction, but what are the conditions for using the variation notations of enthalpy ie. reaction and formation enthalpy?

Jayasuriya Senthilvelan 4I
Posts: 31
Joined: Thu Jan 10, 2019 12:17 am

Re: Standard / Formation / Reaction

Postby Jayasuriya Senthilvelan 4I » Mon Feb 04, 2019 10:52 am

Standard = the enthalpy value has a nought (o) as a superscript. It means that the reactants are all in their standard states.
Reaction = the enthalpy value associated with some reaction.
Formation = enthalpy value associated with the formation of one mole of a particular substance from its substituent elements.

From this we have:
standard enthalpy of formation - enthalpy value associated with formation of one mol of substance from its elements all in their standard states.
standard enthalpy of reaction - enthalpy value for a reaction where all reactants/products are in their standard states
enthalpy of reaction - same as above, but no guarantee that reactants are at standard state.


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