Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are -382.64 kJ mol-1 and -145.6 J K mol-1, respectively. Standard Gibb's energy change for the same reaction at 298 K is
-221.1 kJ mol-1
-339.3. kJ mol-1
-439.3 kJ mol-1
-523.2 kJ mol-1
Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is
Ssystem + Ssurrounding > 0
Ssystem - Ssurrounding > 0
Ssystem > 0 only
Ssurrounding > 0 only
According to the third law of thermodynamics which one of the following quantities for a perfectly crystalline solid is zero at absolute zero ?
Free energy
Entropy
Enthalpy
Internal energy
The correct relationship between free energy and equilibrium constant K of a reaction is
Go = - RT In K
G = RT In K
Go = RT In K
G = - RT In K
The enthalpy and entropy change for the reaction
Br2 (l) + CI2 (g) → 2BrCI (g)
are 30 kJ mol-1 and 105 JK mol-1 respectively. The temperature at which the reaction will be in equilibrium is
285.7 K
273 K
450 K
300 K
A chemical reaction will be spontaneous if it is accompanied by a decrease in
entropy of the system
enthalpy of the system
internal energy of the system
free energy of the system
For the reaction,
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l) at constant temperature, H - E is
+ 3RT
- RT
+ RT
- 3RT
For the gas phase reaction,
PCI5 (g) PCI3(g) + CI2(g)
Which of the following conditions are correct ?
ΔH = 0 and ΔS < 0
ΔH > 0 and ΔS > 0
ΔH < 0 and ΔS < 0
ΔH > 0 and ΔS < 0
If enthalpies of formation of C2H4(g), CO2(g) and H2O(l) at 25oC and 1 atm pressure are 52, -394 and -286 kJ/mol, the enthalpy of combustion of ethene is equal to
-141.2 kJ/mol
-1412 kJ/mol
+14.2 kJ/mol
+1412 kJ/mol
2 moles of an ideal gas at 270 C temperature is expanded reversibly from 2 L to 20 L. Find entropy change (R = 2 cal/mol K).
92.1
0
4
9.2
