HARD
JEE Main
IMPORTANT
Earn 100

Calculate the equilibrium constant (K) for the following reaction at 400 K.

2NOCl(g)2NO(g)+Cl2(g)

Given that ΔrHo=80.0 kJ mol-1and ΔrSo=120 J K-1mol-1 at 400 K.

Use 10-4.178=6.634×10-5 

Important Questions on Thermodynamics

HARD
JEE Main
IMPORTANT

Sodium carbonate (Na2CO3) can be obtained by heating sodium hydrogen carbonate, NaHCO3.

2NaHCO3(s)Na2CO3(s)+H2O(g)+CO2(g)

Calculate the temperature above which NaHCO3 decomposes to form products at 1bar.

Given, enthalpy of formation values, Hfo(kJmol-1) :

NaHCO3(s)=-947.7, Na2CO3(s)=-1130.9, H2O(g)=-241.8, CO2(g)=-393.5

Entropy values, So(JK-1mol-1) : NaHCO3(s)=102.1, Na2CO3(s)=136.0, H2O(g)=188.8, CO2(g)=213.7.

MEDIUM
JEE Main
IMPORTANT

i 2Zn+O22ZnO; G=-161 J

ii 2Zn+2S2ZnS; G=-293 J

iii 2S+2O22SO2; G=-408 J

What would be G for the following reaction?

2ZnS+3O22ZnO+2SO2

HARD
JEE Main
IMPORTANT

The equilibrium constant for the reaction given below is 2.0×10-7 at 300 K. Calculate the standard free energy change for the reaction:

PCl5 gPCl3 g+Cl2 g

HARD
JEE Main
IMPORTANT
Two moles of an ideal gas is expanded isothermally and irreversibly at 27°C from volume V1 to 2.5V1 and 4.17 kJ heat is absorbed from surroundings. Determine ΔSsys, ΔSsurr and ΔSuniv .
HARD
JEE Main
IMPORTANT

An ideal mono-atomic gas was at 1 atm and 300 K. If one mole of such ideal gas is allowed to expand adiabatically against a constant pressure of 0.3 atm till double its volume, determine S in JK-1mol-1 for the process.

Given: log 2=0.3; log 3=0.48; log 5=0.7

MEDIUM
JEE Main
IMPORTANT
The enthalpy of vaporization of water at 100°C is 40.63 kJmol-1. Its entropy of vaporization would be
HARD
JEE Main
IMPORTANT
For a reaction A(g)B(g) at equilibrium, the partial pressure of B is found to be one-fourth of the particle pressure of A. The value of ΔG° of the reaction AB is
HARD
JEE Main
IMPORTANT

The value of log10 K for a reaction AB is

(Given ΔrHo298 K=-54.07 kJ mol-1, ΔrSo298 K=10 JK-1 mol-1 and R=8.314 JK-1 mol-1; 2.303×8.314×298=5705)