Change in enthalpy for reaction
2H2O2(l) → 2H2O(l) + O2 (g)
if heat of formation of H2O2(l) and H2O(l) are -188 and -286 kJ/mol respectively is,
-196 kJ/mol
+ 196 kJ/mol
+ 948 kJ/mol
-948 kJ/mol
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 entropy change in the fusion of one mole of a solid melting at 27o C (latent heat of fusion is 2930 J mol-1 ) is
9.77 J K-1 mol-1
10.73 J K-1 mol-1
2930 J K-1 mol-1
108.5 J K-1 mol-1
In a closed insulated container a liquid is stirred with a paddle to increase the temperature, which of the following is true ?
E = W ≠ 0, q = 0
E = W = 0, q = 0
E =0,W =q ≠ 0
W =0,E =q ≠ 0
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
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
Bond dissociation enthalpy of H2,CI2 and HCI are 434, 242 and 431 kJ mol-1 respectively. Enthalpy of formation of HCI is
93 kJ mol-1
-245 kJ mol-1
-93 kJ mol-1
245 kJ mol-1
Standard Gibb's free energy change for the isomerisation reaction
cis-2-pentene trans-2-pentene is -3.67 kJ/mol at 400 K. If more trans-2-pentene is added to the reaction vessel, then
more cis-2-pentene is formed
equilibrium remains unaffected
additional trans-2-pentene is formed
equilibrium is shifted in forward direction
Consider the following reaction occurring in an automobile
2C8H18(g) + 25O2(g) → 16 CO2(g) + 18 H2O(g)
The sign of ΔH, ΔS, and ΔG would be
+, -, +
-, +, -
-, +, +
+, +, -
PbO2→PbO,G298 < 0
SnO2→ SnO,G298 > 0
Most probable oxidation state of Pb and Sn will be
Pb4+, Sn4+
Pb4+, Sn2+
Pb2+, Sn2+
Pb2+, Sn4+
