Problem 145
For the reaction, \(\mathrm{Ag}_{2} \mathrm{O}(\mathrm{s}) \rightleftharpoons 2 \mathrm{Ag}(\mathrm{s})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g})\) \(\Delta \mathrm{H}, \Delta \mathrm{S}\) and \(\mathrm{T}\) are \(40.657 \mathrm{~kJ} \mathrm{~mol}^{-1}, 109 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\) and \(373 \mathrm{~K}\) respectively. Find the free energy change \((\Delta \mathrm{G})\) of the reaction.
Problem 147
Heat required to raise the temperature of \(1 \mathrm{~mol}\) of a substance by \(1^{\circ}\) is called (a) specific heat (b) molar heat capacity (c) water equivalent (d) specific gravity
Problem 149
A heat engine absorbs heat \(\mathrm{Q}_{1}\) from a source at tem perature \(\mathrm{T}_{1}\) and heat \(\mathrm{Q}_{2}\) from a source at temperature \(\mathrm{T}_{2}\). Work done is found to be \(\mathrm{J}\left(\mathrm{Q}_{1}+\mathrm{Q}_{2}\right)\). This is in accordance with: (a) first law of thermodynamics (b) second law of thermodynamics (c) joules equivalent law (d) none of these
Problem 150
The correct relationship between free energy change in a reaction and the corresponding equilibrium constant \(K_{c}\) is (a) \(\Delta \mathrm{G}=\mathrm{RT}\) In \(\mathrm{K}\) (b) \(-\Delta \mathrm{G}=\mathrm{RT}\) In \(\mathrm{K}\) (c) \(\Delta \mathrm{G}^{\circ}=\mathrm{RT} \operatorname{In} \mathrm{K}_{\mathrm{c}}\) (d) \(-\Delta \mathrm{G}^{\circ}=\mathrm{RT} \operatorname{In} \mathrm{K}_{\mathrm{c}}\)
Problem 151
If at \(298 \mathrm{~K}\) the bond energies of \(\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}\) and \(\mathrm{H}-\mathrm{H}\) bonds are respectively \(414,347,615\) and \(435 \mathrm{~kJ} \mathrm{~mol}^{-1}\), the value of enthalpy change for the reaction \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \longrightarrow \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{3}(\mathrm{~g})\) at \(298 \mathrm{~K}\) will be (a) \(+250 \mathrm{~kJ}\) (b) \(-250 \mathrm{~kJ}\) (c) \(+125 \mathrm{~kJ}\) (d) \(-125 \mathrm{~kJ}\)
Problem 154
The internal energy change when a system goes from state \(\mathrm{A}\) to \(\mathrm{B}\) is \(40 \mathrm{~kJ} / \mathrm{mol}\). If the system goes from \(\mathrm{A}\) to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy? (a) \(40 \mathrm{~kJ}\) (b) \(>40 \mathrm{~kJ}\) (c) \(<40 \mathrm{~kJ}\) (d) zero
Problem 155
An ideal gas expands in volume from \(1 \times 10^{-3} \mathrm{~m}^{3}\) to 1 \(\times 10^{-2} \mathrm{~m}^{3}\) at \(300 \mathrm{~K}\) against a constant pressure of \(1 \times\) \(10^{5} \mathrm{Nm}^{-2}\). The work done is (a) \(-900 \mathrm{~kJ}\) (b) \(-900 \mathrm{~J}\) (c) \(270 \mathrm{~kJ}\) (d) \(940 \mathrm{~kJ}\)
Problem 156
The enthalpies of combustion of carbon and carbon monoxide are \(-393.5\) and \(-283 \mathrm{~kJ} \mathrm{~mol}^{-1}\) respectively. The enthalpy of formation of carbon monoxide per mole is (a) \(-676.5 \mathrm{~kJ}\) (b) \(-110.5 \mathrm{~kJ}\) (c) \(110.5 \mathrm{~kJ}\) (d) \(676.5 \mathrm{~kJ}\)
Problem 157
If the bond dissociation energies of \(\mathrm{XY}, \mathrm{X}_{2}\) and \(\mathrm{Y}_{2}\) are in the ratio of \(1: 1: 0.5\) and \(\Delta \mathrm{H}_{f}\) for the formation of \(\mathrm{XY}\) is \(-200 \mathrm{~kJ} / \mathrm{mole}\). The bond dissociation energy of \(\mathrm{X}_{2}\) will be ? (a) \(100 \mathrm{~kJ} / \mathrm{mole}\) (b) \(400 \mathrm{~kJ} / \mathrm{mole}\) (c) \(600 \mathrm{~kJ} / \mathrm{mole}\) (d) \(800 \mathrm{~kJ} / \mathrm{mole}\)
Problem 158
Consider the reaction \(\mathrm{N}_{2}+3 \mathrm{H}_{2} \rightleftharpoons 2 \mathrm{NH}_{3}\) carried out at constant temperature and pressure. If \(\Delta \mathrm{H}\) and \(\Delta \mathrm{U}\) are the enthalpy and internal energy changes for the reaction, which of the following expressions is true? (a) \(\Delta \mathrm{H}=0\) (b) \(\Delta \mathrm{H}=\Delta \mathrm{U}\) (c) \(\Delta \mathrm{H}<\Delta \mathrm{U}\) (d) \(\Delta \mathrm{H}>\Delta \mathrm{U}\)
