Enthalpy

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What is Enthalpy?

Enthalpy (H) is a thermodynamic quantity equal to the internal energy of a system plus the product of its pressure and volume (H = U + PV). The change in enthalpy (ΔH) at constant pressure equals the heat absorbed or released in a chemical reaction. Exothermic reactions have negative ΔH; endothermic reactions have positive ΔH. Standard enthalpy values are measured at 298 K and 1 atm.

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Term Enthalpy

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What is Enthalpy?

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1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide C8H18ClN3 2-Ethoxyethanol C4H10O2 Effective Collisions Effective Collisions E ≥ Ea (activation energy required) Effective Molality m_eff = i × m (van't Hoff factor) Effective Nuclear Charge Z_eff = Z − σ (Slater's rules) Efflorescence Hydrated salt losing water in air: M·nH₂O(s) → M·(n-x)H₂O(s) + xH₂O(g) Einsteinium Es Electrical Conductivity κ = 1/ρ; Λm = κ/c Electrochemical Cell Galvanic cell: ΔG = −nFE_cell; Electrolytic cell: ΔG = +nFE_applied Electrochemical Series Arranged by E° (standard reduction potential); SHE: E° = 0.00 V Electrochemistry E° cell = E° cathode − E° anode | ΔG° = −nFE°

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