Skip to main content
Ch.9 - Thermochemistry: Chemical Energy
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Non è quello che usi tu?Cambia libro di testo
Capitolo 9, Problema 64

What is the enthalpy change (ΔH) for a reaction at a constant pressure of 1.00 atm fi the internal energy chagne (ΔE) is 44.0 kJ and the volume increase is 14.0 L? (1 L-atm = 101.325 J)

Guida verificata passo dopo passo
1
Identify the relationship between enthalpy change (\( \Delta H \)) and internal energy change (\( \Delta E \)) using the formula: \( \Delta H = \Delta E + P\Delta V \).
Convert the volume change from liters to joules using the conversion factor: \( 1 \text{ L-atm} = 101.325 \text{ J} \). Calculate \( P\Delta V \) in joules.
Substitute the given values into the formula: \( \Delta H = 44.0 \text{ kJ} + (1.00 \text{ atm} \times 14.0 \text{ L} \times 101.325 \text{ J/L-atm}) \).
Convert the \( \Delta E \) from kilojoules to joules if necessary, to ensure consistent units when adding to \( P\Delta V \).
Add the calculated \( P\Delta V \) to \( \Delta E \) to find the enthalpy change \( \Delta H \) in joules, and convert back to kilojoules if needed.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Enthalpy (ΔH)

Enthalpy is a thermodynamic quantity that represents the total heat content of a system at constant pressure. It is defined as the sum of the internal energy of the system and the product of its pressure and volume (ΔH = ΔE + PΔV). Enthalpy changes are crucial for understanding heat transfer in chemical reactions, especially when they occur at constant pressure.
Video consigliato:
Percorso guidato
02:34
Enthalpy of Formation

Internal Energy (ΔE)

Internal energy is the total energy contained within a system, including kinetic and potential energies of the particles. The change in internal energy (ΔE) during a reaction reflects the energy absorbed or released. It is a key component in calculating enthalpy changes, as it provides the baseline energy state of the system before any work or heat transfer occurs.
Video consigliato:
Percorso guidato
00:40
Internal Energy

Work Done by the System (PΔV)

In thermodynamics, work done by a system during a volume change at constant pressure is given by the product of pressure and the change in volume (PΔV). This term accounts for the energy required to expand or compress the system against external pressure. Understanding this concept is essential for calculating the total enthalpy change when a reaction involves a change in volume.
Video consigliato:
Percorso guidato
02:06
Entropy of the System