In thermodynamics, the term 'system' refers to

In thermodynamics, the term 'system' refers to

• A. Everything around the universe
• B. The chemical reaction we are examining
• C. The solvent outside of the reaction
• D. The calorimeter material only

Answer: (B)

The system is the part of the universe you choose to study, defined by a boundary. When you’re examining a chemical reaction, you treat the reacting substances (and, if you include it, the solvent within the reaction vessel) as that system. The rest—the surroundings—lies outside the boundary and can exchange energy with the system, but isn’t part of it. This framing lets us talk about heat, work, and changes in energy for just the chosen portion. So, selecting the chemical reaction we are examining as the system captures the intended focus, whereas the other options describe regions outside that defined study area.

The system is the part of the universe you choose to study, defined by a boundary. When you’re examining a chemical reaction, you treat the reacting substances (and, if you include it, the solvent within the reaction vessel) as that system. The rest—the surroundings—lies outside the boundary and can exchange energy with the system, but isn’t part of it. This framing lets us talk about heat, work, and changes in energy for just the chosen portion. So, selecting the chemical reaction we are examining as the system captures the intended focus, whereas the other options describe regions outside that defined study area.