Problem 18 - Chemistry: The Central Science

Question

In a thermodynamic study a scientist focuses on the properties of a solution in an apparatus as illustrated. A solution is continuously flowing into the apparatus at the top and out at the bottom, such that the amount of solution in the apparatus is constant with time. (a) Is the solution in the apparatus a closed system, open system, or isolated system? Explain your choice. (b) If it is not a closed system, what could be done to make it a closed system?

Step-by-Step Solution

Answer

The solution in the apparatus is an open system because it exchanges both matter (solution) and energy with its surroundings. To make the given open system a closed system, the flow of the solution into and out of the apparatus should be stopped, which would allow the apparatus to exchange energy but prevent the exchange of matter with its surroundings.

Step 1: Understanding the thermodynamic systems

To answer this question, we first need to understand the three types of thermodynamic systems: 1. Closed System: A system that can exchange energy but not matter with its surroundings. 2. Open System: A system that can exchange both energy and matter with its surroundings. 3. Isolated System: A system that cannot exchange energy or matter with its surroundings.

Step 2: Classify the given system

The problem states that the solution is continuously flowing into and out of the apparatus, maintaining a constant amount of solution inside the apparatus. Since the apparatus can exchange matter (the solution) and energy (due to the properties of the solution), it is an open system.

Step 3: Answering part (a)

As we have determined in Step 2, the solution in the apparatus is an open system because it exchanges both matter (solution) and energy with its surroundings.

Step 4: Converting it into a closed system

The problem asks us to change the system into a closed system if it's not already one. Since it's an open system, we need to make adjustments to allow energy exchange but restrict the exchange of matter between the apparatus and its surroundings. One possible way to make the apparatus a closed system is by stopping the flow of the solution into and out of the apparatus. This can be achieved by, for example, turning off the inflow and outflow sources, which would make the apparatus have a constant amount of solution without any exchange of matter between the apparatus and its surroundings. The system can still exchange energy with its surroundings.

Step 5: Answering part (b)

In order to make the given open system a closed system, the flow of the solution into and out of the apparatus should be stopped. This will allow the apparatus to exchange energy with its surroundings, but it will prevent the exchange of matter, which would make it a closed system.