Problem 86
If the standard entropies of \(\mathrm{CH}_{4}(\mathrm{~g}), \mathrm{H}_{2} \mathrm{O}(\mathrm{g}), \mathrm{CO}_{2}(\mathrm{~g})\) and \(\mathrm{H}_{2}(\mathrm{~g})\) are \(186.2,188.2,197.6\) and \(130.6 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively, then the standard entropy change for the reaction \(\mathrm{CH}_{4}(\mathrm{~g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \longrightarrow \mathrm{CO}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g})\) is (a) \(215 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (b) \(225 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (c) \(145 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (d) \(285 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\)
Problem 87
Two moles of an ideal gas are compressed at \(300 \mathrm{~K}\) from a pressure of 1 atm to a pressure of 2 atm. The change in free energy is (a) \(5.46 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(2.46 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(3.46 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(8.46 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
Problem 88
In monoatomic gases, ratio of specific heat at constant pressure to that at constant volume is (a) \(3 / 5\) (b) \(5 / 3\) (c) \(7 / 5\) (d) \(4 / 5\)
Problem 89
The standard entropies of \(\mathrm{H}_{2}(\mathrm{~g}), \mathrm{I}_{2}(\mathrm{~s})\) and \(\mathrm{HI}(\mathrm{g})\) are \(130.6,116.7\) and \(206.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\) respectively. The change in standard entropy in the reaction \(\mathrm{H}_{2}(\mathrm{~g})+\mathrm{I}_{2}(\mathrm{~s}) \longrightarrow 2 \mathrm{HI}(\mathrm{g})\) is (a) \(185.6 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (b) \(170.5 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (c) \(169.5 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (d) \(165.9 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\)
Problem 90
In the reaction: \(\mathrm{CO}(\mathrm{g})+1 / 2 \mathrm{O}_{2}(\mathrm{~g}) \longrightarrow \mathrm{CO}_{2}(\mathrm{~g})\) the change in \(\Delta \mathrm{S}^{\circ}\) is (given \(\mathrm{S}^{\circ}\) for \(\mathrm{CO}, \mathrm{O}_{2}\) and \(\mathrm{CO}_{2}\) are \(197.6,205.3\) and \(213.6 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively) (a) \(-78.6 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (b) \(-50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (c) \(-86.5 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) (d) \(-30 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\)
Problem 91
One mole of an ideal gas is allowed to expand reversibly and adiabatically from a temperature of \(27^{\circ} \mathrm{C}\). If work done during the process is \(3 \mathrm{~kJ}\), then final temperature of the gas is \(\left(\mathrm{C}_{\mathrm{v}}=20 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)\) (a) \(150 \mathrm{~K}\) (b) \(200 \mathrm{~K}\) (c) \(175 \mathrm{~K}\) (d) \(225 \mathrm{~K}\)
Problem 92
The change in entropy, in the conversion of one mole of water at \(373 \mathrm{~K}\) to vapour at the same temperature is (Latent heat of vaporization of water = \(\left.2.257 \mathrm{~kJ} \mathrm{~g}^{-1}\right)\) (a) \(99 \mathrm{JK}^{-1}\) (b) \(129 \mathrm{JK}^{-1}\) (c) \(89 \mathrm{JK}^{-1}\) (d) \(109 \mathrm{JK}^{-1}\)
Problem 94
One mole of monatomic ideal gas at \(\mathrm{T}(\mathrm{K})\) is expanded from \(1 \mathrm{~L}\) to \(2 \mathrm{~L}\) adiabatically under a constant external pressure of 1 atm the final temperature of the gas in Kelvin is (a) \(\mathrm{T}\) (b) \(\frac{\mathrm{T}}{2^{5 / 3-2}}\) (c) \(\mathrm{T}-\frac{2}{3 \times 0.0821}\) (d) \(T+\frac{3}{2 \times 0.0821}\)
Problem 95
One mole of a non-ideal gas undergoes a change of state \((2.0 \mathrm{~atm}, 3.0 \mathrm{~L}, 95 \mathrm{~K}) \longrightarrow(4.0 \mathrm{~atm}, 5.0 \mathrm{~L}\) \(245 \mathrm{~K}\) ) with a change in internal energy, \(\Delta \mathrm{U}=30.0 \mathrm{~L}\) atm. The change in enthalpy \((\Delta H)\) of the process in \(L\) atm is (a) \(40.0\) (b) \(42.3\) (c) \(44.0\) (d) not defined, because pressure is not constant
Problem 96
The \(\Delta \mathrm{H}_{\mathrm{f}}^{\circ}\) for \(\mathrm{CO}_{2}(\mathrm{~g}), \mathrm{CO}(\mathrm{g})\) and \(\mathrm{H}_{2} \mathrm{O}(\mathrm{g})\) are \(-393.5\), \(-110.5\) and \(-241.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\) respectively. The standard enthalpy change (in \(\mathrm{kJ}\) ) for the reaction \(\mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \longrightarrow \mathrm{CO}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})\) is (a) \(524.1\) (b) \(41.2\) (c) \(-262.5\) (d) \(-41.2\)
