Something that cannot exchange matter with the environment (if this would be physics, we would also have to forbid any exchange of energy).mech-eng said:
It does not matter what changes, the mass stays constant in every case.mech-eng said:
Its average temperature and pressure are changing, although there may be variations of temperature and pressure with spatial location within the system. The average specific volume of a closed system is, of course, constant, but the specific volume may be varying with spatial position within the system. The term "closed system undergoing a change" means that work is being done on the system at its boundary and/or heat is being exchanged with the surroundings at its boundary.mech-eng said:
Chestermiller said:
Can you please provide a more detailed example of this?mech-eng said:
Chestermiller said:
Are you envisioning an electrical resistor inside the system connected by wires to the outside, with electrical current flowing through the wires so that the resistor is giving off heat?mech-eng said:
Chestermiller said:
You could also have electrical wires running to a fan. Would you include that too?mech-eng said:
Chestermiller said:
Who says it's not related to the boundaries? If you include the resistor or the fan as part of your system, then the electrical wires are passing through the exterior boundary of the system, with one wire carrying current into the system at a higher voltage, and the other wire carrying current out of the system at a lower voltage. So the electrical work is being done at the boundary of your system.mech-eng said:
Chestermiller said:
Like you said, you are not very familiar with electricity.mech-eng said:
The conservation of mass for a closed system is a fundamental principle in physics and chemistry that states that the total mass of a closed system remains constant over time. This means that mass cannot be created or destroyed, only transformed or transferred within the system.
In chemical reactions, the total mass of the reactants is equal to the total mass of the products. This is known as the law of conservation of mass, which is a direct consequence of the conservation of mass for a closed system.
An open system is one that exchanges both matter and energy with its surroundings, while a closed system only exchanges energy but not matter. This means that in a closed system, the total mass remains constant, while in an open system, the mass can change due to matter entering or leaving the system.
The conservation of mass is important in environmental science because it helps us understand and predict the impact of human activities on the environment. It allows us to track the movement of pollutants and understand how they can affect different ecosystems and the overall balance of the Earth's systems.
The conservation of mass is a well-established principle in physics, and it has been confirmed through countless experiments and observations. However, in certain extreme cases, such as nuclear reactions, mass can be converted into energy, violating the conservation of mass. But in everyday situations, the conservation of mass is always true and can be used to make accurate predictions and calculations.