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Topic: does Standard Temperature and Pressure have different temperatures?  (Read 2226 times)

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Offline Jekel0000

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Does the STP have different temperatures depending on what PHASE the MATTER is in...
Ex STP of a Gas would be 0° C
and STP of a liquid would be 25°C

IS THAT CORRECT????

Offline Xenonman

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I understood your title better than your post.

Answering the title's question, yes, there are different "standard" temperatures and pressures. http://en.wikipedia.org/wiki/Standard_temperature_and_pressure. Someone else may answer why this happens.
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Offline Borek

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Does the STP have different temperatures depending on what PHASE the MATTER is in...

No.

As Xenonman already said, there are different STP standards - it depends on who defined them and for what applications. But they are not related to the state of matter of the substance.

This is a little bit messy, whenever you see someone referring to STP you should ask them what they mean by that.
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Offline Jekel0000

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Re: does Standard Temperature and Pressure have different temperatures?
« Reply #3 on: November 17, 2014, 04:49:30 PM »
because this is the question I was trying to answer in the Chemical Reactive Energy portion of my General Chemistry text...I assumed the Standard State is Solid, Liquid, Gas, or Plasma...At a specified Temperature...

5) What is the value of the standard enthalpy of formation for any element under standard conditions?
Standard enthalpies of formation for the elements in their standard states are zero, because:
standard conditions are normally expressed as STP(standard Temperature and Pressure) which is normally 25°C at 1 bar approximately 1 atm(760 torr). The standard state of Oxygen at STP is a gas and until the gas is changed to a liquid the standard enthalpy of formation is standardized as one scalar quantity before change of state occurs for the liquid, but once the change occurs from the gas to the liquid the scalar quantity of the ∆H(standard enthalpy of formation) will change to a different value.

NOTE: The standard state of Carbon at STP exists in three different solid states Graphite, Diamond, and Buckminsterfullerene.

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