9-3-enthalpy_glossary
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Browse the glossary using this index
Special | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | ALL
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Endothermic ReactionA reaction that absorbs heat from the surroundings (ΔH > 0). | |
Enthalpy (H)A thermodynamic state function defining the total heat content of a system at constant pressure. | |
Enthalpy Change (ΔH)The heat flow (q) at constant pressure. A negative value indicates an exothermic reaction, while a positive value indicates an endothermic reaction. | |
Exothermic ReactionA reaction that releases heat to the surroundings (ΔH < 0). | |
F |
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First Law of ThermodynamicsThe total energy of a system and its surroundings remains constant. | |
H |
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Hess's LawThe enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps of the reaction. | |
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Internal Energy (U)The sum of all possible kinds of energy present in a substance. | |
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Standard Enthalpy of Combustion (ΔH°comb)The enthalpy change when 1 mole of a substance burns completely in oxygen under standard conditions. | |
Standard Enthalpy of Formation (ΔH°f)The enthalpy change when 1 mole of a substance is formed from its elements in their standard states. | |
Standard StateA commonly accepted set of conditions (1 bar pressure, 1 M concentration for solutions, and usually 298.15 K) used as a reference point for thermodynamic properties. | |