Chemical Engineering Basics - Engineering

Q1:

At absolute zero temperature, for any reaction involving condensed phases

A Δ G° = 0 , Δ H° = 0

B Δ H° = 0 , Δ S° = 0

C Δ S° = 0 , Δ E° = 0

D Δ S° = 0 , Δ Cp° = 0

ANS:C - Δ S° = 0 , Δ E° = 0

At absolute zero temperature (T=0 K), the entropy of any system approaches zero (ΔS∘=0). This is because entropy is a measure of the disorder or randomness of a system, and at absolute zero, molecular motion ceases, resulting in minimal disorder. Therefore, the correct statement is: ΔS∘=0, Δ,0ΔCp∘=0 At absolute zero temperature, the enthalpy (ΔH∘) and the Gibbs free energy (ΔG∘) may or may not be zero depending on the specific reaction. However, in many cases, the enthalpy and the Gibbs free energy can still have non-zero values at absolute zero temperature. Therefore, the other options are not necessarily true for all reactions involving condensed phases at absolute zero temperature.