Two nonpolar organic liquids, hexane (C₆H₁₄) and heptane (C₇H₁₆), are mixed. (b) Hexane and heptane are miscible with each other in all proportions. In making a solution of them, is the entropy of the system increased, decreased, or close to zero, compared to the separate pure liquids?

Key Concepts

Entropy

Entropy is a measure of the disorder or randomness in a system. In thermodynamics, it quantifies the number of ways a system can be arranged, with higher entropy indicating greater disorder. When two substances mix, such as hexane and heptane, the overall disorder of the system typically increases, leading to a higher entropy state compared to the separate pure liquids.

Miscibility

Miscibility refers to the ability of two substances to mix in all proportions without separating into different phases. Hexane and heptane are both nonpolar organic liquids, which allows them to mix completely. This property is crucial in understanding how the mixing of these liquids affects the system's entropy, as miscible liquids tend to increase disorder upon mixing.

Thermodynamic Favorability

Thermodynamic favorability relates to the tendency of a process to occur spontaneously based on changes in energy and entropy. When hexane and heptane mix, the increase in entropy generally makes the mixing process thermodynamically favorable. This means that the system's overall energy state is lowered, and the process is likely to occur naturally, contributing to the increase in entropy.