Chemical Thermodynamics

The entropy (S°) of the following substances are :

$\ce{CH4}$ (g) 186.2 J K$^{-1}$ mol$^{-1}$
$\ce{O2}$ (g) 205.0 J K$^{-1}$ mol$^{-1}$
$\ce{CO2}$ (g) 213.6 J K$^{-1}$ mol$^{-1}$
$\ce{H2O}$ ($l$) 69.9 J K$^{-1}$ mol$^{-1}$

The entropy change (ΔS°) for the reaction
$$\ce{CH4(g) + 2O2(g) -> CO2(g) + 2H2O(l)}$$
is :

The standard enthalpy of formation ($\Delta_fH^\circ_{298}$) for methane, $\ce{CH4}$ is $-74.9$ kJ mol$^{-1}$. In order to calculate the average energy given out in the formation of a C−H bond from this it is necessary to know which one of the following ?

The standard enthalpies of formation of $\ce{CO2}(g)$, $\ce{H2O}(l)$ and glucose(s) at 25 °C are −400 kJ/mol, −300 kJ/mol and −1300 kJ/mol, respectively. The standard enthalpy of combustion per gram of glucose at 25 °C is

Benzene and naphthalene form an ideal solution at room temperature. For this process, the true statement(s) is(are)

The thermal dissociation equilibrium of $\ce{CaCO3}(s)$ is studied under different conditions.
$$\ce{CaCO3(s) <=> CaO(s) + CO2(g)}$$
For this equilibrium, the correct statement(s) is(are)

The pair of isochoric processes among the transformation of states is

For an ideal gas, consider only $P$-$V$ work in going from an initial state $X$ to the final state $Z$. The final state $Z$ can be reached by either of the two paths shown in the figure. Which of the following choice(s) is (are) correct? [take $\Delta S$ as change in entropy and $w$ as work done]

Using the data provided, calculate the multiple bond energy (kJ mol⁻¹) of a C≡C bond in $\ce{C2H2}$. That energy is (take the bond energy of a C-H bond as 350 kJ mol⁻¹.)

$\ce{2C(s) + H2(g) -> C2H2(g)}$, $\Delta H=225$ kJ mol⁻¹

$\ce{2C(s) -> 2C(g)}$, $\Delta H=1410$ kJ mol⁻¹

$\ce{H2(g) -> 2H(g)}$, $\Delta H=330$ kJ mol⁻¹

The reversible expansion of an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?

Match the transformations in column I with appropriate options in column II

The species which by definition has ZERO standard molar enthalpy of formation at 298 K is

The bond energy (in kcal mol⁻¹) of a C-C single bond is approximately

Among the following, the intensive property is (properties are)

One mole of an ideal gas is taken from a to b along two paths denoted by the solid and the dashed lines as shown in the graph below. If the work done along the solid line path is $w_s$ and that along the dotted line path is $w_d$, then the integer closest to the ratio $w_d/w_s$ is

Among the following, the state function(s) is(are)

In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in excess oxygen at 298.0 K. The temperature of the calorimeter was found to increase from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of the calorimeter is 2.5 kJ K$^{-1}$, the numerical value for the enthalpy of combustion of the gas in kJ mol$^{-1}$ is

STATEMENT-1: For every chemical reaction at equilibrium, standard Gibbs energy of reaction is zero.

and

STATEMENT-2: At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.

STATEMENT-1: There is a natural asymmetry between converting work to heat and converting heat to work.

and

STATEMENT-2: No process is possible in which the sole result is the absorption of heat from a reservoir and its complete conversion into work.

The value of $\log_{10}K$ for a reaction $\ce{A <=> B}$ is

(Given: $\Delta_rH^\circ_{298K}=-54.07$ kJ mol⁻¹, $\Delta_rS^\circ_{298K}=10$ J K⁻¹ mol⁻¹ and $R=8.314$ J K⁻¹ mol⁻¹; $2.303\times8.314\times298=5705$)

For the process $\ce{H2O}(l)$ (1 bar, 373 K) → $\ce{H2O}(g)$ (1 bar, 373 K), the correct set of thermodynamic parameters is