Question

In an open system, both ............. and ............. can cross the boundary?

• A. Heat and mass
• B. Work and energy
• C. Mass and energy
• D. Pressure and volume

Hint:

In an open system, both mass and energy can move across the boundary, which distinguishes it from closed or isolated systems.

Answer 1

The Correct Option is C

In an open system, both mass and energy can cross the boundary. An open system allows the exchange of both matter (mass) and energy with its surroundings.
- Heat and mass are incorrect because heat is a form of energy transfer, not a material quantity that crosses the boundary like mass.
- Work and energy are related, but in an open system, energy crosses the boundary, not work. Work is a process that transfers energy, but it is not a substance that can pass across the boundary.
- Pressure and volume are thermodynamic parameters related to the state of the system, but neither can cross the boundary as substances.
Thus, the correct answer is (3), Mass and energy.