Thermodynamics

If 100 mole of H2O2 decompose at 1 bar and 300 K, the work done (kJ) by one mole of O2(g) as it expands against 1 bar pressure is :
2H2O2(l)    \(\rightleftharpoons\)    2H2O(l) + O2(g)
(R = 8.3 J K \(-\)1 mol\(-\)1)

The heats of combustion of carbon and carbon monoxide are –393.5 and –283.5 kJ mol–1, respectively. The
heat of formation (in kJ) of carbon monoxide per mole is :

The following reaction is performed at 298 K
2NO(g) + O2 (g) \(\leftrightharpoons\) 2NO2 (g)
The standard free energy of formation of NO(g) is 86.6 kJ/mol at 298 K. What is the standard free energy
of formation of NO2(g) at 298 K? (KP = 1...

For complete combustion of ethanol, C2H5OH(l) + 3O2(g) \(\to\) 2CO2(g) + 3H2O(l) the amount of heat
produced as measured in bomb calorimeter, is 1364.47 kJ mol–1 at 25oC. Assuming ideality the Enthalpy of combustion, \(\Delta _CH\), for th...

A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant
temperature of 37.0oC. As it does so, it absorbs 208J of heat. The values of q and w for the process will be :
(R = 8.314 J/mol K) ( l n 7...

The incorrect expression among the following is :

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a
volume of 10 dm3 to a volume of 100 dm3 at 27oC is :

The standard enthalpy of formation of NH3 is –46.0 kJ mol–1. If the enthalpy of formation of H2 from its atoms is –436 kJ mol–1 and that of N2 is –712 kJ mol–1, the average bond enthalpy of N–H bond in NH3 is :

For a particular reversible reaction at temperature T, ∆H and ∆S were found to be both +ve. If Te is
the temperature at equilibrium, the reaction would be spontaneous when :

On the basis of the following thermochemical data : (\(\Delta _fG^oH^+_{(aq)}\) = 0)

H2O(l) \(\to\) H+(aq) + OH-(aq); \(\Delta H\) = 57.32 kJ
H2(g) + \({1 \over 2} O_2(g) \to\) H2O(l); \(\Delta H\) = -286.20 kJ
The value of enthalpy of for...

Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated
below:
\({1 \over 2}C{l_2}(g)\) \(\buildrel {{1 \over 2}{\Delta _{diss}}{H^\Theta }} \over \longrightarrow\) \(Cl(g)\) $$\buildrel {{\Delta _{e...

Standard entropy of X2, Y2 and XY3 are 60, 40 and 50 JK−1
mol−1 , respectively. For the reaction,
\({1 \over 2} X_2\) + \({3 \over 2} Y_2 \to\) XY3, \(\Delta H\) = -30 kJ, to be at equilibrium, the temperature will be :

Assuming that water vapour is an ideal gas, the internal energy change \(\left( {\Delta U} \right)\) when \(1\) mol of water is vapourised at \(1\) bar pressure and \({100^ \circ }C\) (Given : molar enthalpy of vapourisation of water at $$1...

In conversion of lime-stone to lime,
CaCO3(s) \(\to\) CaO(s) + CO2 (g) the vales of ∆H° and ∆S° are +179.1 kJ mol−1
and 160.2 J/K respectively at 298 K and 1 bar.
Assuming that ∆H° do not change with temperature, temperature above which c...

Identify the correct statement regarding a spontaneous process :

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If Ti is the
initial temperature and Tf is the final temperature, which of the following statements is correct?

The enthalpy changes for the following processes are listed below :
Cl2(g) = 2Cl(g), 242.3 kJ mol–1
I2(g) = 2I(g), 151.0 kJ mol–1
ICl(g) = I(g) + Cl(g), 211.3 kJ mol–1
I2(s) = I2(g), 62.76 kJ mol–1
Given that the standard states for iod...

(\(\Delta H - \Delta U\)) for the formation of carbon monoxide (CO) from its elements at 298 K is : (R = 8.314 J K–1 mol–1)

The standard enthalpy of formation \(\Delta _fH^o\) at 298 K for methane, CH4(g), is –74.8 kJ mol–1. The additional information required to determine the average energy for C – H bond formation would be :

If the bond dissociation energies of XY, X2 and Y2 (all diatomic molecules) are in the ratio of 1:1:0.5 and \(\Delta H_f\) for the formation of XY is -200 kJ mole-1. The bond
dissociation energy of X2 will be :

Consider an endothermic reaction, X \(\to\) Y with the activation energies Eb and Ef
for the backward and forward reactions, respectively. In general :

Consider the reaction: N2 + 3H2 \(\to\) 2NH3 carried out at constant temperature and
pressure. If \(\Delta H\) and \(\Delta U\) are the enthalpy and internal energy changes for the
reaction, which of the following expressions is true?

The enthalpies of combustion of carbon and carbon monoxide are -393.5 and -283 kJ mol-1
respectively. The enthalpy of formation of carbon monoxide per mole is :

An ideal gas expands in volume from 1\(\times\)10-3 m3 to 1 \(\times\) 10-2 m3 at 300 K against a constant pressure of 1\(\times\)105 Nm-2. The work done is :

In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria :

The correct relationship between free energy change in a reaction and the corresponding equilibrium constant Kc is :

The enthalpy change for a reaction does not depend upon :

The internal energy change when a system goes from state A to B is 40 kJ/mole. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy?

If at 298 K the bond energies of C - H, C - C, C = C and H - H bonds are respectively 414, 347, 615 and 435 kJ/mol, the value of enthalpy change for the reaction
H2C = CH2(g) + H2(g) \(\to\) H3C - CH3(g) at 298 K will be :

If an endothermic reaction is non-spontaneous at freezing point of water and becomes feasible at its boiling point, then :

The heat required to raise the temperature of body by 1 K is called :

A heat engine absorbs heat Q1 at temperature T1 and heat Q2 at temperature T2. Work done by the engine is J (Q1 + Q2). This data :

For the reactions
2C + O2 \(\to\) 2CO2; \(\Delta H\) = -393 J
2Zn + O2 \(\to\) 2ZnO; \(\Delta H\) = -412 J