What is the difference between an “open” system & a “closed” system?

2 Answers

A thermodynamically-closed system doesn't allow new objects to wander into the experiment, whereas a thermodynamically-open system allows the matter to exchange between. Both allow energy transfer.

Explanation:

If a new substance is accidentally introduced into the system, the outcome could be different, but if it is closed, you should always get similar results.

A thermodynamically-closed system and thermodynamically-open system are both subject to the second law of thermodynamics. Entropy of the universe doesn't decrease for both kinds of systems (because we live in a physical world of irreversible processes).

Explanation:

A thermodynamically-closed system has that energy, but not matter, can enter or leave the system.

The universe is considered to be a closed system. The universe is also subject to the second law of thermodynamics, which means that the change in energy dispersal or entropy in the universe is always nonnegative for real-life (irreversible) processes.

A thermodynamically-open system is again subject to the second law of thermodynamics, but new matter and energy can enter the system.

The earth is an open system with respect to the universe. Energy from the sun can enter the system creating new sources of energy, matter in the form of cosmic dust, asteroids and meteoroids can enter the earth's system.

In most chemical experiments, it is important to achieve a closed system (as much as possible). A closed system will allow valid conclusions to be formed about mass.