What are the conditions for thermodynamic equilibrium?

Answer

To determine the conditions for thermodynamic equilibrium, we need to consider three essential types of equilibrium that a system must satisfy simultaneously. These conditions are:

### Step-by-Step Solution:

1. **Mechanical Equilibrium**:
- A system is in mechanical equilibrium when the net force acting on it is zero. This means that all forces acting on the system are balanced, and there is no acceleration.
- **Condition**: Net force = 0

2. **Chemical Equilibrium**:
- A system is in chemical equilibrium when there are no net changes in the composition of the system. This occurs when the chemical reactions within the system have reached a state where the rates of the forward and reverse reactions are equal, resulting in no overall change in the concentrations of reactants and products.
- **Condition**: No net reaction occurs within the system.

3. **Thermal Equilibrium**:
- A system is in thermal equilibrium when it is at the same temperature as its surroundings, meaning there is no temperature gradient between the system and the environment. This implies that heat transfer between the system and its surroundings has ceased.
- **Condition**: Temperature of the system = Temperature of the surroundings.

### Conclusion:
For a system to be in thermodynamic equilibrium, it must satisfy all three conditions simultaneously:
- Mechanical equilibrium (Net force = 0)
- Chemical equilibrium (No net reaction occurs)
- Thermal equilibrium (Temperature of the system = Temperature of the surroundings)