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Topic: Enthalpy of fusion

	Standard enthalpy change of fusion Summary
		The heat of fusion is the heat that is absorbed to transform a substance from its solid state to its liquid state at constant, that is, to melt the solid substance.
		Enthalpies of fusion are positive because the solid state affords the molecules or ions that compose a pure substance the opportunity to maximize their attractive interactions with each other.
		The standard enthalpy change of fusion, also known as the heat of fusion, is the amount of thermal energy which must be absorbed or lost for 1 gram of a substance to change states from a solid to a liquid or vice versa.
	www.bookrags.com /Standard_enthalpy_change_of_fusion (1435 words)

	Key Experimental Data
		This precise evaluation of the rate of enthalpy generation relies on the non-linear regression fitting of the "fl-box" model of the calorimeter to an extensive set of temperature time measurements.
		The method of data analysis gives a systematic underestimate of the enthalpy output and, in consequence, a slightly negative excess rate of enthalpy generation for an extensive set of blank experiments using both light and heavy water.
		It is also shown that prolonged polarization of palladium cathodes in heavy water leads to bursts in the rate of enthalpy generation: the thermal output of the cells exceeds the enthalpy input (or the total energy input) to the cells by factors in excess of 40 during these bursts.
	www.infinite-energy.com /resources/keyexpdata.html (4915 words)

	Calorimetric Equivalence Principle Test
		Benzil melts between 94-95 C, 112 joules/gram enthalpy of fusion (latent heat of melting).
		For each orientation a paired opposite parity enthalpy of fusion of benzil is run at local 0600 hrs, noon, 1800 hrs, and midnight to cycle maximum signal, null, maximum, and null signals from the phase angle of Earth's inertial spin and gravitational orbit.
		Racemic benzil powder enthalpy of fusion is 112 joules/gram.
	www.mazepath.com /uncleal/lajos.htm (4175 words)

	Lab Experiment:Calculating Molar Enthalpy of Fusion of Water Text - Physics Forums Library
		I am doing a lab experiment in school to find the molar enthalpy of fusion of water.
		Ice and water are mixed in a calorimeter and the temperatures are recorded.
		finding the change in enthalpy of water(q=mct)then dividing it by the # of moles of ice (6.61g/18.02g/mol) gives me a value of -5691 J. This value from your data is closer to the molar enthalpy of fusion of ice.
	www.physicsforums.com /archive/index.php/t-55429.html (829 words)

	U.S. Navy Cold Fusion research
		We do not know if Cold Fusion will be the answer to future energy needs, but we do know the existence of Cold Fusion phenomenon through repeated observations by scientists throughout the world.
		It is time that this phenomenon be investigated so that we can reap whatever benefits accrue from additional scientific understanding.
		The synopsis: " No sooner had cold fusion surfaced than it was written off, and the idea of extracting virtually limitless free energy from water became taboo.
	www.lenr-canr.org /Collections/USNavy.htm (1710 words)

	D2Fusion
		The number of flash-in-the-pan "believers" had diminished, and the "skeptics" were beginning to be faced with having to explain the anomalous phenomenon, which by this time had been observed by many credible scientists throughout the world.
		At China Lake, Dr. Miles and his collaborators showed that a correlation exists between the rate of the excess enthalpy generation and the quantity of helium in the gas stream.
		The emphasis is on the interpretation of data and the accuracy of the determination of the excess enthalpy generation via the appropriate selection of heat transfer coefficients.
	www.d2fusion.com /education/navy_report.html (1373 words)

	Standard enthalpy change of fusion - Wikipedia, the free encyclopedia
		Standard enthalpy change of fusion of period two of the periodic table of elements.
		The standard enthalpy change of fusion, also known as the heat of fusion, is the amount of thermal energy which must be absorbed or lost for 1 gram of a substance to change states from a solid to a liquid or vice versa.
		It is also called the latent heat of fusion or the enthalpy of fusion, and the temperature at which it occurs is called the melting point.
	en.wikipedia.org /wiki/Standard_enthalpy_change_of_fusion (540 words)

	[No title]
		An adiabatic calorimeter was used to measure the enthalpy of fusion of a sample of high-purity bismuth.
		The new value of the enthalpy of fusion was determined to be Hfus = (53.146 +/- 0.082) J.g-1, where the uncertainty corresponded to a 95% confidence interval.
		The temperature of fusion of this sample was found not to differ with previous accurate determinations within the accuracy of the fusion-temperature determination made in the present study.
	www.boulder.nist.gov /div838/trc/journals/jced/2004v49/i05/je049913p.xml (96 words)

	Quiz 1A Answers (Site not responding. Last check: )
		The enthalpy of sublimation of mercury is 61.6 kJ/mol and its enthalpy of vaporization is 59.3 kJ/mol.
		The enthalpy of fusion is the enthalpy for melting one mole of a substance and is always positive.
		Because enthalpy is a state function, the enthalpy of sublimation is equal to the enthalpy of fusion plus the enthalpy of vapourization.
	www.chembio.uoguelph.ca /balahura/quiz_answers.html (485 words)

	General Chemistry Online: Glossary: Liquids
		) heat of fusion; molar heat of fusion; molar enthalpy of fusion.
		Enthalpies of fusion are always positive because melting involves overcoming some of the intermolecular attractions in the solid.
		Enthalpies of vaporization are always positive because vaporization involves overcoming most of the intermolecular attractions in the liquid.
	antoine.frostburg.edu /chem/senese/101/liquids/glossary.shtml (1153 words)

	General Chemistry Online: Glossary:
		Enthalpy is formally defined as H = U + PV, where U is the internal energy, P is the pressure, and V is the volume.
		Enthalpies of hydration for ions are always negative because strong ion-water attractions are formed when the gas-phase ion is surrounded by water.
		Enthalpies of sublimation are always positive because vaporization involves overcoming most of the intermolecular attractions in the sublimation.
	antoine.frostburg.edu /chem/senese/101/glossary/e.shtml (1830 words)

	Erik's Chemistry: First Law of Thermodynamics Terms
		They lie at a higher enthalpy than their component elements and have a positive standard enthalpy of formations.
		The standard enthalpy of a reaction is the sum of the standard enthalpies of the reactions into which the overall reaction may be divided.
		The standard enthalpy (per mole of substance) of a for its formation from its elements in their reference states.
	members.tripod.com /~EppE/pc2term.htm (658 words)

	Recent Publications by NIST Authors (Site not responding. Last check: )
		An adiabatic calorimeter was used to measure the enthalpy of fusion of a very pure sample of indium.
		The new value of the enthalpy of fusion was determined to be {delta}^dfus^H = (28.6624 ± 0.0076) J·g^u-1^, where the uncertainty corresponded to a 95% confidence interval.
		The temperature of fusion of this sample was found to not differ with the ITS-90 assigned value within the accuracies of the thermometry used in the present study.
	ois.nist.gov /nistpubs/technipubs/recent/search.cfm?dbibid=12927 (142 words)

	Untitled Document (Site not responding. Last check: )
		So, as long as there is both ice and water together the temperature is constant and all of the heat put into the system will go into the enthalpy of fusion.
		When we put heat into the system, some ice melts, breaking down the attractive forces between the molecules in the ice, and withdrawing energy (the enthalpy of fusion) from the system.
		If we were to try and take heat out of the system, ice would form, releasing the enthalpy of fusion into the system and again keeping the temperature constant.
	www.public.asu.edu /~laserweb/woodbury/classes/chm341/assign6/pots2_8.htm (125 words)

	College Chemistry: Thermodynamics
		During changes in state, the heat of fusion and heat of vaporization are used.
		The spontaneity of a process (shown with a negative free energy value) is found by relating enthalpy, entropy and temperature to find free energy.
		The heat changes of physical processes will be introduced using specific heat capacity, heats of fusion and vaporization, and calorimetry.
	www.chemistry24.com /college_chemistry/thermodynamics.html (434 words)

	Journal of the Brazilian Chemical Society - Thermodynamic study of the solubility of some sulfonamides in cyclohexane (Site not responding. Last check: )
		The thermodynamic functions Gibbs energy, enthalpy and entropy of solution in cyclohexane, were evaluated from solubility data for a group of sulfonamides over the temperature range from 20.0 to 40.0 °C. The excess Gibbs energy and the activity coefficients of the solutes were also determined.
		There are only a few values of enthalpy and entropy of fusion reported in the literature, and they have been obtained by differential thermal analysis (DTA), a semiquantitative method, while the values presented here were obtained by DSC, a quantitative method, the latter being more appropriate for the determination of molar enthalpies of fusion.
		The enthalpy of fusion may be considered as the heat required to increase the intermolecular distances in crystals, allowing melting to occur.
	www.scielo.br /scielo.php?pid=S0103-50532003000500016&script=sci_arttext&tlng=en (2729 words)

	Studies on the Interaction of Water with Ethylcellulose: Effect of Polymer Particle Size
		The extrapolated melting peak onset temperature for pure water was 0.913°C, and melting peak temperature was 4.24°C. The experimental enthalpy of fusion of pure water was 316 J/g, which was used as the basis for calculations.
		In general, the enthalpy of fusion of pure water is between 311 and 334 J/g because of the formation of various polymorphic forms of ice.
		The melting enthalpy of this peak was less than that of pure water added to the sample, indicating that some of the bound water does not freeze; thus, in the present study, the nonfreezing bound water content was determined from the difference between the actual water content and the freezing water content as follows:
	www.aapspharmscitech.org /view.asp?art=pt040460 (5164 words)

	Paper 2005-06
		The heat capacity of ethyl undecanoate was measured between 110 K and 365 K; the compound crystallized in a metastable form, which recrystallized slowly to the stable crystalline state during heating.
		The triple-point temperature of the stable form was found to be (259.17 ± 0.04) K, and the enthalpy of fusion was (36.1 ± 0.1) kJ·mol
		The metastable form crystallized at 251.3 K. The heat capacity of ethyl tridecanoate was measured between 175 K and 320 K; the compound also crystallized in a metastable form, which recrystallized during heating to the stable form.
	www.chem.uu.nl /ctg/publ/abstracts/2005-06.htm (137 words)

	Element (Site not responding. Last check: )
		A transuranium element, only a few atoms of bohrium have ever been made, and it will probably never be isolated in observable quantities.
		Created by the so-called "cold fusion" method, in which a target of bismuth is bombarded with atoms of chromium.
		A synthetic element created via nuclear bombardment, few atoms have ever been made and the properties of bohrium are very poorly understood.
	www.ucc.ie /ucc/depts/chem/dolchem/html/newelement107.htm (285 words)

	unit03-sect02-les01-lessona (Site not responding. Last check: )
		Molar enthalpies for a number of species undergoing chemical or physical changes are known.
		Melting (fusion) is an endothermic process - energy is required to break the intermolecular forces that hold water molecules together in the ice crystal.
		The molar enthalpy of fusion of 5.0 L is 13.37 kJ/mol.
	www.cdli.ca /courses/chem3202/unit03/section02/lesson02/3-lesson-a.htm (1112 words)

	Chapter 11, Section 4 (Site not responding. Last check: )
		Thus, the enthalpy change associated with melting a solid is often called the enthalpy of fusion, or heat of fusion, which we denote
		The heat of fusion of ice is 6.01 kJ/mol.
		Calculate the enthalpy change upon converting 1.00 mol of ice at -25°C to water vapor (steam) at 125°C under a constant pressure of 1 atm.
	cwx.prenhall.com /bookbind/pubbooks/brown/chapter11/medialib/blb1104.html (1518 words)

	SparkNotes: SAT Chemistry: Enthalpy
		Often chemical changes result in either the release or the absorption of heat, and this change in heat in the system is measured in terms of the system’s enthalpy (H).
		First of all, enthalpy is a state function, meaning that its value is fixed when temperature, pressure, composition, and physical form are specified.
		Finally, the enthalpy changes of a reaction can be calculated in several ways, including by using stoichiometry, calorimetry, tables of standard values, Hess’s law, and the bond energies of the substances involved.
	www.sparknotes.com /testprep/books/sat2/chemistry/chapter9section1.rhtml (456 words)

	Heat - Latent Heat
		This means that to convert 1 kg of ice at 0 ºC to 1 kg of water at 0 ºC, 334 kJ of heat must be absorbed by the ice.
		Latent heats of fusion vary widely, and values should always be accompanied by the temperatures at which they were measured (these are not necessarily the normal melting points).
		For example, the enthalpy of fusion of ice at 0º is 6.01 kJ.mol
	www.physchem.co.za /Heat/Latent.htm (794 words)

	Enthalpy Table \| Issue9mm
		Enthalpy fusion; Enthalpy of formation; Define enthalpy; Calculate enthalpy; Enthalpy entropy; Enthalpy table; There is never listed, since in this new variable is the thermochemistry menu.
		The calculator then outputs the pressure or temperature, the specific volume, the enthalpy, and the...
		Enthalpy of vaporization; Enthalpy table; Chart co2 enthalpy; Substituting enthalpy into the enthalpy mass, enthalpy they.
	www.issue9mm.com /enthalpytable.html (170 words)

	Chemistry: WebElements Periodic Table : Periodic properties : Enthalpy of fusion: Definition
		Chemistry: WebElements Periodic Table: Professional Edition: Definitions: Enthalpy of fusion
		Select from the menu to the left to view pictures illustrating the Enthalpy of fusion.
		Copyright 1993-2007 Mark Winter [The University of Sheffield and WebElements Ltd, UK].
	www.webelements.com /webelements/properties/text/definitions/enthalpy-fusion.html (180 words)

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