Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 ~K are -382.64 ~kJ ~mol^ -1 and -145.6 JK^ -1 ~mol^ -1 , respectively. Standard Gibbs energy change for the same reaction at 298 ~K is:

Correct answer: B. -339.3 ~kJ ~mol^ -1 Δ G=Δ H-T Δ S=-382.64-298((-145.6)/(1000)) aligned & =-382.64+43.38 & =-339.3 ~kJ ~mol^ -1 aligned Related Theory Free energy is an extensive quantity, but the standard free energy is an intensive quantity.

NEET 2004

Exam: NEET
Year: 2004
Subject: Chemistry
Chapter: Thermodynamics (C)

NEET 2004 · Chemistry · Thermodynamics (C)

Standard enthalpy and standard entropy changes for the oxidation of...

Standard enthalpy and standard entropy changes for the oxidation of ammonia at

298 \mathrm{~K}

are

-382.64 \mathrm{~kJ} \mathrm{~mol}^{-1}

and -145.6

\mathrm{JK}^{-1} \mathrm{~mol}^{-1}

, respectively. Standard Gibbs energy change for the same reaction at

298 \mathrm{~K}

is:

Options

A $-221.1 \mathrm{~kJ} \mathrm{~mol}^{-1}$
B $-339.3 \mathrm{~kJ} \mathrm{~mol}^{-1}$
C $-439.3 \mathrm{~kJ} \mathrm{~mol}^{-1}$
D $-523.2 \mathrm{~kJ} \mathrm{~mol}^{-1}$

Correct answer

B. $-339.3 \mathrm{~kJ} \mathrm{~mol}^{-1}$

Step-by-step solution

\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta \mathrm{S}=-382.64-298\left(\frac{-145.6}{1000}\right)

\begin{aligned}& =-382.64+43.38 \\ & =-339.3 \mathrm{~kJ} \mathrm{~mol}^{-1} \end{aligned}

$$Related Theory Free energy is an extensive quantity, but the standard free energy is an intensive quantity.

Practice Thermodynamics (C) on Quantrex Academy →

More from Thermodynamics (C)