What is the relationship between enthalpy and internal energy at constant pressure?
Practice Questions
1 question
Q1
What is the relationship between enthalpy and internal energy at constant pressure?
ΔH = ΔU + PΔV.
ΔH = ΔU - PΔV.
ΔH = ΔU.
ΔH = PΔV.
At constant pressure, the change in enthalpy (ΔH) is related to the change in internal energy (ΔU) and the pressure-volume work done (PΔV) by the equation ΔH = ΔU + PΔV.
Questions & Step-by-step Solutions
1 item
Q
Q: What is the relationship between enthalpy and internal energy at constant pressure?
Solution: At constant pressure, the change in enthalpy (ΔH) is related to the change in internal energy (ΔU) and the pressure-volume work done (PΔV) by the equation ΔH = ΔU + PΔV.
Steps: 5
Step 1: Understand that enthalpy (H) is a measure of total energy in a system, including internal energy and the energy required to make space for it (pressure-volume work).
Step 2: Recognize that internal energy (U) is the energy contained within the system itself, excluding any work done by the system on its surroundings.
Step 3: At constant pressure, the change in enthalpy (ΔH) can be expressed as the change in internal energy (ΔU) plus the work done due to volume change (PΔV).
Step 4: The equation that relates these quantities is ΔH = ΔU + PΔV.
Step 5: This means that if you know how much the internal energy changes and how much work is done due to volume change, you can find the change in enthalpy.
