Problem 20 - 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 thermodynamic system, as it exchanges both matter and energy with its surroundings due to the continuous flow of the solution. To make it a closed system, we could close off the inlet and outlet, disconnecting the apparatus from the source and sink of the solution, ensuring no exchange of matter while still allowing energy exchange.

Step 1: Determine the type of thermodynamic system

To determine the type of thermodynamic system, let's first understand the definitions of each type: 1. Closed System: A system that is capable of exchanging energy (heat and work), but not matter, with its surroundings. 2. Open System: A system that is capable of exchanging both energy (heat and work) and matter with its surroundings. 3. Isolated System: A system that does not exchange any matter or energy with its surroundings. In the given setup, the solution flows continuously into and out of the apparatus. This means the solution in the apparatus is exchanging matter (solution) with its surroundings, making it an open system.

Step 2: Explanation of the open thermodynamic system

Since the solution flows into and out of the apparatus, the apparatus continuously exchanges both matter and energy (such as heat and work) with its surroundings. Consequently, the solution in the apparatus cannot be a closed system (no matter exchange) or an isolated system (no matter or energy exchange). Therefore, the solution in the apparatus is an open thermodynamic system.

Step 3: Making the apparatus a closed system

In order to make the apparatus a closed system, we need to prevent the exchange of matter (in this case, the solution) with the surroundings while still allowing energy exchange. This can be achieved by closing off the inlet and outlet, such that solution no longer flows in or out of the apparatus. By disconnecting the apparatus from the source and sink of the solution, we ensure that the amount of solution in the apparatus remains constant, allowing the system to exchange energy, but not matter, thus converting it into a closed thermodynamic system.