Question

Which of the following processes have a ΔS < 0?

Which of the following processes have a ΔS < 0?

methanol (g, at 555 K) → methanol (g, at 400 K)

isopropyl alcohol condenses

carbon dioxide(g) → carbon dioxide(s)

water freezes

All of the above processes have a ΔS < 0.

Answer 1

methanol (g, at 555 K) → methanol (g, at 400 K)

at lower temperature molecular motion will be slow so less disorderness at lower temperature.

in above reaction changes from high T to lower T. so entropy will decrease.

S < 0

isopropyl alcohol condenses

condensation means gas converts to liquid. means more disorder to less disorder means decrease in entropy.

so S < O

carbon dioxide(g) → carbon dioxide(s)

gas changes to solid. means more disorder gas changes to less disorder solid so entropy will decrease.

S < 0

water freezes

liquid state changes to solid state. so entropy will decrease

S < 0

All of the above processes have a ΔS < 0. correct statement.