Problem 32 - Chemistry An Atoms First Approach

Question

Which of the following involve an increase in the entropy of the system? a. melting of a solid b. sublimation c. freezing d. mixing e. separation f. boiling

Step-by-Step Solution

Answer

The processes that involve an increase in entropy are: melting of a solid (a), sublimation (b), mixing (d), and boiling (f). These processes result in an increase in randomness or disorder within the system.

Step 1: a. Melting of a solid

Melting involves a solid turning into a liquid. During this process, the particles in the solid gain kinetic energy, causing them to move more freely. Therefore, the randomness of the system increases. Thus, melting of a solid results in an increase in entropy.

Step 2: b. Sublimation

Sublimation is the process in which a solid transitions directly into a gas, bypassing the liquid state. In this process, the particles in the solid break their bonds and move independently as a gas. The randomness of the system increases during this transition. Thus, sublimation involves an increase in entropy.

Step 3: c. Freezing

Freezing is the process of a liquid becoming a solid. As the liquid particles lose kinetic energy, they become more ordered, forming the rigid structure of a solid. Therefore, the randomness in the system decreases. Thus, freezing does not involve an increase in entropy.

Step 4: d. Mixing

During the mixing process, two or more substances are combined into a mixture. The particles of different substances are distributed randomly, increasing the disorder in the system. Mixing, therefore, involves an increase in entropy.

Step 5: e. Separation

Separation is the process of separating two or more substances from a mixture. This process results in a more ordered system, as the particles of different substances are arranged separately. Therefore, separation does not involve an increase in entropy.

Step 6: f. Boiling

Boiling involves a liquid transitioning into a gas. In this process, the particles in the liquid gain enough kinetic energy to break their bonds and move freely as a gas. The randomness of the system increases during boiling. Thus, boiling involves an increase in entropy. In conclusion, the processes that involve an increase in entropy are: melting of a solid (a), sublimation (b), mixing (d), and boiling (f).