The enthalpy of combustion for the H2, cyclohexene and cyclohexane are -241, -3800 and -3920 kJ mol-1 respectively. Heat of hydrogenation of cyclohexene is
121 kJ mol-1
-121 kJ mol-1
242 kJ mol-1
-242 kJ mol-1
If Hf (H2O) is -286.20 kJ mol-1, then H (OH-) is
-228.88 kJ mol-1
+228.88 kJ mol-1
-343.52 kJ mol-1
+343.52 kJ mol-1
1 mole of gas occupying 3 L volume is expanded against a constant external pressure of 1 atm to a volume of 15 L. The work done by a system is equal to
-1.215 × 103 J
-12.15 × 103 J
+1.215 × 103 J
+12.15 × 103 J
Which one of the following is not a state function?
Internal energy
Work
Entropy
Free energy
B.
Work
The variable depending only upon the initial and final states of a system but not on the path followed are called state functions, eg internal energy, entropy and free energy. Work done is a path function.
Given that N2(g) + 3H2(g) → 2NH3(g): ΔrH° =-92kJ, the standard molar enthalpy of formation in kJ mol-1 of NH3(g) is
-92
+46
+92
-46
In view of for the following reactions
PbO2 + Pb → 2PbO,
SnO2 + Sn → 2SnO,
Which oxidation state is more characteristic for lead and tin?
For lead +2, for tin +2
For lead +4, for tin +4
For lead +2, for tin +4
For lead +4, for tin +2
The enthalpy of the formation of CO2 and H2O are -395 kJ and -285 kJ respectively and the enthalpy of combustion of acetic acid is 869 kJ. The enthalpy of formation of acetic acid is
340 kJ
420 kJ
491 kJ
235 kJ
Considering entropy(s) as a thermodynamic parameter, the criterion for the spontaneity of any process, the change in entropy is
Standard enthalpy (heat) of formation of liquid water at 25°C is around
H2(g) + O2(g) → H2O (l)
-237 kJ/mol
237 kJ/mol
- 286 kJ/mol
286 kJ/mol
Given ΔHf° for CO2(g) , CO(g) and H2O(g) are -393.5, -110.5 and -241.8 kJ mol-1, respectively. The ΔHf° [in kJ mol-1] for the reaction
CO2(g) + H2(g) → CO(g) + H2O (g) is
524.1
-262.5
-417
412