what is the standard molar enthalpy for any element by itself?
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The standard enthalpy of formation for an element in its standard state is ZERO!!!! Elements in their standard state are not formed, they just are. So, ΔH°f for C (s, graphite) is zero, but the ΔH°f for C (s, diamond) is 2 kJ/mol. That is because graphite is the standard state for carbon, not diamond.
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The relevant standard enthalpy of formation values from Table 1 are: O2(g): 0 kJ/mol. NO(g): 90.25 kJ/mol. NO2(g): 33.18 kJ/mol.
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The standard enthalpy of reaction (ΔHorxn) can be calculated from the sum of the standard enthalpies of formation of the products (each multiplied by its stoichiometric coefficient) minus the sum of the standard enthalpies of formation of the reactants (each multiplied by its stoichiometric coefficient)—the “products ...
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The standard enthalpy of formation is the change in enthalpy that accompanies the formation of one mole of the compound from its elements. The standard enthalpy of reaction occurs in a system when one mole of matter is transformed by a chemical reaction.
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The standard molar heat of vaporization for water is 40.79 kJ/mol. How much energy would be required to vaporize 94.0 g of water? The standard molar heat of vaporization for water is 40.79 kJ/mol.
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Standard Molar Enthalpy of Formation. standard molar enthalpy of formation: the enthalpy change of a chemical reaction in which one mole of a pure substance is formed from the free elements in their most stable states under standard state conditions.
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Although diamond is made up of single element but every carbon atom is connected with 4 different carbons which causes it's enthalpy of formation non zero. Elements in their standard state are not formed, they just are. So, ΔH°f for C (s, graphite) is zero, but the ΔH°f for C (s, diamond) is 2 kJ/mol.
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Truong-Son N. It's just the heat/enthalpy of reaction for a hydrogenation reaction. You can determine this from the standard enthalpies of formation. where R is reactants, P is products, n is the stoichiometric coefficient, H is enthalpy, and ∘ labels the enthalpy as the "standard" enthalpy ( T=25∘C and P=1 atm ).
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See section on enthalpy for a more detailed explanation. ... The standard enthalpy of reaction is symbolized by ΔHº or ΔHºrxn and can take on both positive and negative values. The units for ΔHº are kiloJoules per mole, or kj/mol.
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The standard state of a material is a reference point for the material's thermodynamic state properties such as enthalpy, entropy, Gibbs free energy, etc. ... The standard enthalpy of formation is the change in enthalpy that accompanies the formation of one mole of the compound from its elements.
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All elements in their standard states (oxygen gas, solid carbon in the form of graphite, etc.) have a standard enthalpy of formation of zero, as there is no change involved in their formation.
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The enthalpy change that accompanies melting of one mole of a solid substance in standard state is called standard enthalpy of fusion.
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The standard enthalpy of formation of a pure element is in its reference form its standard enthalpy formation is zero.
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One mole (abbreviated mol) is equal to 6.022×1023 molecular entities (Avogadro's number), and each element has a different molar mass depending on the weight of 6.022×1023 of its atoms (1 mole). The molar mass of any element can be determined by finding the atomic mass of the element on the periodic table.
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Bond enthalpy (also known as bond energy) is defined as the amount of energy required to break one mole of the stated bond. For example, the bond energy of a O-H single bond is 463 kJ/mol.
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The standard enthalpy of formation of NH3(g) at 298 K is –46 kJ mol–1.
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The standard enthalpy of formation for sucrose(s) is -2221.2 kJ/mol.