Question

Predict the sign of entropy change in following: $H_{2}O(at \ 298 K, 1 atm) \longrightarrow H_{2}O$ (at 330 K, 1 atm)

Answer 1

"Entropy is a "measure" of the lack of thermal energy of any mechanical work system. It also represents the system's randomness. As randomness increases the system entropy. Entropy of the system is directly proportional to the randomness.

Let's predict the sign of entropy change in the following.

$H_{ 2 }O (at\quad298K, 1atm)\quad \longrightarrow \quad H_{ 2 }O\quad (at\quad 330K,1atm)$

Gas at lower pressure has greater randomness than \Delta at high pressure (compressed gas) at the same temperature.

Hence, entropy decreases, i.e., $\Delta S\quad is\quad -ve$."