Question

Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are382.64 kJ mol${}^{-1}$ and 145.6 JK${}^{-1}$ mol${}^{-1}$, respectively. Standard Gibbs energy change for the same reaction at 298 K is:

• A. -339.3 kJ mol${}^{-1}$
• B. 439.3 kJ mol${}^{-1}$
• C. 523.2 kJ mol${}^{-1}$
• D. 221.1 kJ mol${}^{-1}$

Answer 1

The correct option is A -339.3 kJ mol${}^{-1}$

Given that,

$△H=382.64KJ/mol$

$△S=145.6J{K}^{-1}mo{l}^{-1}$

$T=298K$

$△G^o=△H-T△S^o$

By putting the values on the above equation, we get

$△G^o=382.64-(298\times 145.6\times {10}^{-3})$

$=-339.3KJ/mol$.

Therefore, the correct option is $A$