Standard state

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Standard state

Postby ng1D » Sat Jan 25, 2020 1:49 pm

What is the standard state of a substance and how do I know if a substance is in its standard state?

Posts: 53
Joined: Fri Aug 02, 2019 12:16 am

Re: Standard state

Postby DanielTalebzadehShoushtari2A » Sat Jan 25, 2020 1:59 pm

The standard state of a substance is its most stable form at 1 atm and (usually) 25 degrees Celsius. In standard state, gases are at 1 atm, solutions are at 1 M (and also 1 atm), liquids/solids are assumed to be pure, and elements are in their most stable phase.

Wilson 2E
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Re: Standard state

Postby Wilson 2E » Sat Jan 25, 2020 2:05 pm

The standard state is the phase a compound is in at standard conditions (25 C, 1 atm), and is typically indicated for an element on the periodic table.

Sartaj Bal 1J
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Re: Standard state

Postby Sartaj Bal 1J » Sat Jan 25, 2020 2:07 pm

In addition to the response above, most reactions are already provided in their standard state. When all reactants and products are in their standard state, the reaction enthalpy is called standard reaction enthalpy.

Return to “Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)”

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