Thermodynamics Practice Suite
1. What type of process occurs when a system exchanges both heat and work with its surroundings, and there is no change in internal energy?
Verification Matrix:
For an ideal gas, internal energy depends directly on temperature ($\Delta U \propto \Delta T$). Zero change in internal energy ($\Delta U = 0$) implies an **isothermal process** ($\Delta T = 0$). By the First Law ($\Delta Q = \Delta U + \Delta W$), we get $\Delta Q = \Delta W$, meaning heat exchange balances work done exactly.
2. During an isobaric process, what remains constant?
Verification Matrix:
The term *isobaric* comes from the Greek root *baros* (meaning weight/pressure). An **isobaric process** is defined as one in which the system's pressure remains constant throughout ($\Delta P = 0$).
3. In which thermodynamic process does a system exchange heat with its surroundings but undergoes no change in temperature?
Verification Matrix:
An **isothermal process** takes place at a constant temperature ($\Delta T = 0$). Heat transfer occurs continuously to counteract energy losses or gains due to boundary work, maintaining thermal equilibrium.
4. What is the characteristic of an adiabatic process?
Verification Matrix:
An **adiabatic process** is defined as a thermodynamic change where zero thermal energy passes across system boundaries ($\Delta Q = 0$), usually achieved via heavy thermal insulation or high process speed.
5. In an isochoric process, what is the primary feature?
Verification Matrix:
By definition, an **isochoric (or isovolumetric) process** is one that takes place at **constant volume** ($\Delta V = 0$). Because boundary work $W = P\Delta V$, zero work is done ($W = 0$) as a direct consequence of this feature.
6. What is internal energy in a thermodynamic system?
Verification Matrix:
**Internal energy ($U$)** is the microscopic sum of all kinetic energies (translational, rotational, vibrational) and microscopic potential energies (intermolecular bonds) of all constituent particles within the system boundaries.
7. How is the change in internal energy ($\Delta U$) defined in terms of heat ($\Delta Q$) and work ($\Delta W$)?
Verification Matrix:
According to the First Law of Thermodynamics, energy conservation dictates that heat supplied ($\Delta Q$) equals internal energy increase ($\Delta U$) plus work done by the system ($\Delta W$). Rearranging gives **$\Delta U = \Delta Q - \Delta W$**.
8. What is the internal energy of an ideal gas related to?
Verification Matrix:
For an ideal gas, intermolecular potential energy is zero due to the absence of attractive forces. Thus, internal energy consists solely of molecular kinetic energy, which depends **exclusively on absolute temperature** ($U = \frac{f}{2}nRT$), as described by Joule's Law.
9. During an adiabatic expansion process, what happens to the internal energy of the system?
Verification Matrix:
In an adiabatic expansion ($\Delta Q = 0$), the First Law reduces to $\Delta U = -\Delta W$. Because the expanding gas does positive work ($\Delta W > 0$) on its surroundings at the expense of its own thermal storage, $\Delta U$ becomes negative—meaning internal energy **decreases** (causing cooling).
10. What is the equation for the internal energy change of a system in an isochoric process?
Verification Matrix:
In an isochoric process, volume is constant ($\Delta V = 0$), so boundary work is zero ($\Delta W = P\Delta V = 0$). Substituting $\Delta W = 0$ into the First Law ($\Delta U = \Delta Q - \Delta W$) yields **$\Delta U = \Delta Q$**. All heat transferred goes directly toward altering internal energy.
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