First law of thermodynamics - Revision history

202.80.218.34 at 13:58, 19 May 2019

2019-05-19T13:58:08Z

← Older revision		Revision as of 15:58, 19 May 2019
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	==References==		==References==
	#[http://dx.doi.org/10.1098/rstl.1850.0004 James Prescott Joule "On the Mechanical Equivalent of Heat", Philosophical Transactions of the Royal Society of London '''140''' pp. 61-82 (1850)]		#[http://dx.doi.org/10.1098/rstl.1850.0004 James Prescott Joule "On the Mechanical Equivalent of Heat", Philosophical Transactions of the Royal Society of London '''140''' pp. 61-82 (1850)]
			#[http://ailis.lib.unair.ac.id/opac/detail-opac?id=12591 Kenneth Wark "Thermodynamics"]
	[[Category: Classical thermodynamics]]		[[Category: Classical thermodynamics]]

Carl McBride at 09:16, 5 July 2011

2011-07-05T09:16:51Z

← Older revision		Revision as of 11:16, 5 July 2011
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	system and ''W'' is the [[work]] done upon the system. <math>\delta</math> represents an [http://mathworld.wolfram.com/InexactDifferential.html inexact differential], indicating that the resulting value depends on the path taken.		system and ''W'' is the [[work]] done upon the system. <math>\delta</math> represents an [http://mathworld.wolfram.com/InexactDifferential.html inexact differential], indicating that the resulting value depends on the path taken.

	For reversible changes		For reversible changes, where the system evolves through a succession of equilibrium states, one has:

	:<math>\left.dW\right.=-p~dV </math>		:<math>\left.dW\right.=-p~dV </math>

Carl McBride: Added mention of inexact differentials

2011-07-04T11:50:49Z

Added mention of inexact differentials

← Older revision		Revision as of 13:50, 4 July 2011
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	Where ''U'' is the [[internal energy]] of the system, i.e.		Where ''U'' is the [[internal energy]] of the system, i.e.
	ignoring the external energy of the system, for example		ignoring the external energy of the system, for example
	motion of the ~~center~~ of mass of the system, or the presence		motion of the centre of mass of the system, or the presence
	of an external field. ''Q'' is the net [[heat]] entering the		of an external field. ''Q'' is the net [[heat]] entering the
	system and ''W'' is the [[work]] done upon the system.		system and ''W'' is the [[work]] done upon the system. <math>\delta</math> represents an [http://mathworld.wolfram.com/InexactDifferential.html inexact differential], indicating that the resulting value depends on the path taken.

	For reversible changes		For reversible changes

Dduque: Q, W both "upon" the system

2009-06-08T09:09:26Z

Q, W both "upon" the system

← Older revision		Revision as of 11:09, 8 June 2009
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	ignoring the external energy of the system, for example		ignoring the external energy of the system, for example
	motion of the center of mass of the system, or the presence		motion of the center of mass of the system, or the presence
	of an external field. ''Q'' is the [[heat]] and ''W'' is the [[work]].		of an external field. ''Q'' is the net [[heat]] entering the
			system and ''W'' is the [[work]] done upon the system.

	For reversible changes		For reversible changes
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	where <math>p</math> is the [[pressure]] and <math>V</math> is the volume.		where <math>p</math> is the [[pressure]] and <math>V</math> is the volume.

	For an adiabatic system (i.e. a system in which no heat enters or leaves)		For an adiabatic system (i.e. a system in which no heat enters or leaves)
	then if two bodies of different [[temperature \|temperatures]] are placed in contact		then if two bodies of different [[temperature \|temperatures]] are placed in contact

Dduque: link to new adiabatic process

2008-12-12T14:46:22Z

link to new adiabatic process

← Older revision		Revision as of 16:46, 12 December 2008
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	For an adiabatic system (i.e. a system in which no heat enters or leaves)		For an adiabatic system (i.e. a system in which no heat enters or leaves)
	then if two bodies of different [[temperature \|temperatures]] are placed in contact		then if two bodies of different [[temperature \|temperatures]] are placed in contact
	and then separated then the sum of the heat within the system is unchanged.		and then separated then the sum of the heat within the system is unchanged (see
			[[adiabatic process]].
	This is conservation of energy. The first law of thermodynamics does not		This is conservation of energy. The first law of thermodynamics does not
	provide information on the direction of the heat transfer (if any).		provide information on the direction of the heat transfer (if any).

Carl McBride: Added a reference

2008-04-10T14:55:17Z

Added a reference

← Older revision		Revision as of 16:55, 10 April 2008
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	heat to the colder object, the direction of heat flow from hot to cold,		heat to the colder object, the direction of heat flow from hot to cold,
	is left to the [[second law of thermodynamics]].		is left to the [[second law of thermodynamics]].
			==References==
			#[http://dx.doi.org/10.1098/rstl.1850.0004 James Prescott Joule "On the Mechanical Equivalent of Heat", Philosophical Transactions of the Royal Society of London '''140''' pp. 61-82 (1850)]
	[[Category: Classical thermodynamics]]		[[Category: Classical thermodynamics]]

Carl McBride at 15:09, 29 January 2008

2008-01-29T15:09:01Z

← Older revision		Revision as of 17:09, 29 January 2008
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	:<math>\left.dW\right. > -p~dV </math>		:<math>\left.dW\right. > -p~dV </math>

			where <math>p</math> is the [[pressure]] and <math>V</math> is the volume.
	For an adiabatic system (i.e. a system in which no heat enters or leaves)		For an adiabatic system (i.e. a system in which no heat enters or leaves)
	then if two bodies of different temperatures are placed in contact		then if two bodies of different [[temperature \|temperatures]] are placed in contact
	and then separated then the sum of the heat within the system is unchanged.		and then separated then the sum of the heat within the system is unchanged.
	This is conservation of energy. The first law of thermodynamics does not		This is conservation of energy. The first law of thermodynamics does not

Carl McBride at 11:12, 21 June 2007

2007-06-21T11:12:57Z

← Older revision		Revision as of 13:12, 21 June 2007
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	For reversible changes		For reversible changes

	:<math>\left.dW\right.=-~~PdV~~ </math>		:<math>\left.dW\right.=-p~dV </math>

	and for irreversible changes		and for irreversible changes

	:<math>\left.dW\right. > -~~PdV~~ </math>		:<math>\left.dW\right. > -p~dV </math>

	For an adiabatic system (i.e. a system in which no heat enters or leaves)		For an adiabatic system (i.e. a system in which no heat enters or leaves)

Carl McBride at 10:29, 21 June 2007

2007-06-21T10:29:05Z

← Older revision		Revision as of 12:29, 21 June 2007
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	~~Conservation~~ of energy.		The '''first law of thermodynamics''' is a statement of the conservation of energy for thermal processes:

	:<math>\left.dU\right.=\delta Q+ \delta W</math>		:<math>\left.dU\right.=\delta Q+ \delta W</math>
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	of an external field. ''Q'' is the [[heat]] and ''W'' is the [[work]].		of an external field. ''Q'' is the [[heat]] and ''W'' is the [[work]].

	~~Reversible change~~		For reversible changes

	:<math>\left.dW\right.=-PdV </math>		:<math>\left.dW\right.=-PdV </math>

	irreversible ~~change~~		and for irreversible changes

	:<math>\left.dW\right. > -PdV </math>		:<math>\left.dW\right. > -PdV </math>
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	In other words, the common experience that the hotter object gives		In other words, the common experience that the hotter object gives
	heat to the colder object, the direction of heat flow from hot to cold,		heat to the colder object, the direction of heat flow from hot to cold,
	is left to the second law of thermodynamics.		is left to the [[second law of thermodynamics]].
	[[Category: Classical thermodynamics]]		[[Category: Classical thermodynamics]]

Carl McBride at 10:26, 21 June 2007

2007-06-21T10:26:49Z

← Older revision		Revision as of 12:26, 21 June 2007
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	Conservation of energy.		Conservation of energy.

	:<math>\left.dU\right.=dQ+dW</math>		:<math>\left.dU\right.=\delta Q+ \delta W</math>

	Where ~~<math>~~U~~</math>~~ is the [[internal energy]] of the system, i.e.		Where ''U'' is the [[internal energy]] of the system, i.e.
	ignoring the external energy of the system, for example		ignoring the external energy of the system, for example
	motion of the center of mass of the system, or the presence		motion of the center of mass of the system, or the presence
	of an external field.		of an external field. ''Q'' is the [[heat]] and ''W'' is the [[work]].

	Reversible change		Reversible change