Q.Discuss the a. thermal equilibrium b. mechanical equilibrium c. Chemical equilibrium d. thermodynamic equilibrium.

Step 1. Thermal equilibrium: two systems are in thermal equilibrium if they are at the same temperature, which then does not change with time -- e.g. a hot coffee cup cooling until it matches the room's temperature, after which no more net heat flows.

Step 2. Mechanical equilibrium: a system is in mechanical equilibrium if no unbalanced force acts on it (or by it on the surroundings) -- e.g. a gas-piston system, where the piston settles once the upward force from the gas exactly balances the downward weight of the piston plus any added masses.

Step 3. Chemical equilibrium: two systems in contact are in chemical equilibrium if there is no net chemical reaction occurring between them. …

Define each of the three sub-equilibria separately, then state that all three together con …

• Treating 'thermal equilibrium' alone as sufficient for 'thermodynamic equilibrium' -- the full concept additiona …