Chemical Thermodynamics

2 mol of Hg($g$) is combusted in a fixed volume bomb calorimeter with excess of $\ce{O2}$ at 298 K and 1 atm into HgO($s$). During the reaction, temperature increases from 298.0 K to 312.8 K. If heat capacity of the bomb calorimeter and enthalpy of formation of Hg($g$) are 20.00 kJ K$^{-1}$ and 61.32 kJ mol$^{-1}$ at 298 K, respectively, the calculated standard molar enthalpy of formation of HgO($s$) at 298 K is X kJ mol$^{-1}$. The value of $|\mathrm X|$ is _____.

[Given: Gas constant $R = 8.3\ \mathrm{J\,K^{-1}\,mol^{-1}}$]

The correct option(s) about entropy (S) is(are)

[R = gas constant, F = Faraday constant, T = Temperature]

At 25°C and 1 atm pressure, the enthalpies of combustion are as given below:
$$\begin{array}{|l|c|c|c|}\hline \text{Substance}&\mathrm{H_2}&\text{C (graphite)}&\mathrm{C_2H_6(g)}\\\hline \Delta_cH^\ominus\ (\mathrm{kJ\,mol^{-1}})&-286.0&-394.0&-1560.0\\\hline\end{array}$$
The enthalpy of formation of ethane is

The standard entropy change for the reaction
$$\mathrm{4Fe(s)+3O_2(g)\rightarrow2Fe_2O_3(s)}$$
is $-550\ \mathrm{J\,K^{-1}}$ at 298 K.

[Given : The standard enthalpy change for the reaction is $-165\ \mathrm{kJ\,mol^{-1}}$]. The temperature in K at which the reaction attains equilibrium is ______. (Nearest Integer)

At 25°C and 1 atm pressure, the enthalpy of combustion of benzene (l) and acetylene (g) are $-3268\ \mathrm{kJ\,mol^{-1}}$ and $-1300\ \mathrm{kJ\,mol^{-1}}$, respectively. The change in enthalpy for the reaction $\mathrm{3C_2H_2(g)\rightarrow C_6H_6(l)}$, is

For complete combustion of methanol
$$\mathrm{CH_3OH(l)+\tfrac32O_2(g)\rightarrow CO_2(g)+2H_2O(l)}$$
the amount of heat produced as measured by bomb calorimeter is 726 kJ mol$^{-1}$ at 27°C. The enthalpy of combustion for the reaction is $-x$ kJ mol$^{-1}$, where $x$ is ______. (Nearest integer)

(Given : $R=8.3$ J K$^{-1}$ mol$^{-1}$)

A fish swimming in water body when taken out from the water body is covered with a film of water of weight 36 g. When it is subjected to cooking at 100 °C, then the internal energy for vaporization in kJ mol$^{-1}$ is ______. [nearest integer]

[Assume steam to be an ideal gas. Given $\Delta_{\rm vap}H^\ominus$ for water at 373 K and 1 bar is 41.1 kJ mol$^{-1}$; $R=8.31$ J K$^{-1}$mol$^{-1}$]

Match List - I with List - II.

Choose the correct answer from the options given below :

When 5 moles of He gas expand isothermally and reversibly at 300 K from 10 litre to 20 litre, the magnitude of the maximum work obtained is ______ J. [nearest integer] (Given : $R=8.3$ J K$^{-1}$mol$^{-1}$ and $\log2=0.3010$)

4.0 L of an ideal gas is allowed to expand isothermally into vacuum until the total volume is 20 L. The amount of heat absorbed in this expansion is ______ L atm.

For combustion of one mole of magnesium in an open container at 300 K and 1 bar pressure, $\Delta_CH^\ominus=-601.70$ kJ mol$^{-1}$, the magnitude of change in internal energy for the reaction is ______ kJ. (Nearest integer)

(Given : R = 8.3 J K$^{-1}$ mol$^{-1}$)

17.0 g of $\mathrm{NH_3}$ completely vapourises at $-33.42$°C and 1 bar pressure and the enthalpy change in the process is 23.4 kJ mol$^{-1}$. The enthalpy change for the vapourisation of 85 g of $\mathrm{NH_3}$ under the same conditions is ______ kJ.

2.2 g of nitrous oxide ($\mathrm{N_2O}$) gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression of the gas from 217.1 mL to 167.75 mL. The change in internal energy of the process, $\Delta U$ is '$-x$' J. The value of '$x$' is ______. [nearest integer]

(Given: atomic mass of N = 14 g mol$^{-1}$ and of O = 16 g mol$^{-1}$. Molar heat capacity of $\mathrm{N_2O}$ is 100 J K$^{-1}$mol$^{-1}$)

1.0 mol of monoatomic ideal gas is expanded from state 1 to state 2 as shown in the figure. The magnitude of the work done for the expansion of gas from state 1 to state 2 at 300 K is ______ J. (Nearest integer)

(Given : R = 8.3 J K$^{-1}$ mol$^{-1}$, ln10 = 2.3, log2 = 0.30)

The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are $-2220.0$ kJ mol$^{-1}$, $-393.5$ kJ mol$^{-1}$ and $-285.8$ kJ mol$^{-1}$ respectively. The magnitude of enthalpy of formation of propane ($\mathrm{C_3H_8}$) is ______ kJ mol$^{-1}$. (Nearest integer)

While performing a thermodynamics experiment, a student made the following observations.

$\mathrm{HCl+NaOH\rightarrow NaCl+H_2O}$ $\Delta H=-57.3$ kJ mol$^{-1}$

$\mathrm{CH_3COOH+NaOH\rightarrow CH_3COONa+H_2O}$ $\Delta H=-55.3$ kJ mol$^{-1}$

The enthalpy of ionization of $\mathrm{CH_3COOH}$ as calculated by the student is ______ kJ mol$^{-1}$. (nearest integer)

2.4 g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atm pressure. The temperature of the calorimeter rises from 298 K to 300 K. The enthalpy change during the combustion of coal is $-x$ kJ mol$^{-1}$. The value of $x$ is ______. (Nearest Integer)

(Given : Heat capacity of bomb calorimeter 20.0 kJ K$^{-1}$. Assume coal to be pure carbon)

For the reaction

$$\mathrm{H_2F_2(g)\rightarrow H_2(g)+F_2(g)}$$

$\Delta U=-59.6$ kJ mol$^{-1}$ at 27°C.

The enthalpy change for the above reaction is (−) ______ kJ mol$^{-1}$ [nearest integer]

Given: R = 8.314 J K$^{-1}$ mol$^{-1}$.

The molar heat capacity for an ideal gas at constant pressure is 20.785 J K$^{-1}$mol$^{-1}$. The change in internal energy is 5000 J upon heating it from 300 K to 500 K. The number of moles of the gas at constant volume is ______. [Nearest integer] (Given: R = 8.314 J K$^{-1}$ mol$^{-1}$)

A gas (Molar mass = 280 g mol$^{-1}$) was burnt in excess $\mathrm{O_2}$ in a constant volume calorimeter and during combustion the temperature of calorimeter increased from 298.0 K to 298.45 K. If the heat capacity of calorimeter is 2.5 kJ K$^{-1}$ and enthalpy of combustion of gas is 9 kJ mol$^{-1}$ then amount of gas burnt is ______ g. (Nearest Integer)