Problem 31
The enthalpy change involved in the oxidation of glucose is \(-2880 \mathrm{~kJ} / \mathrm{mol}\). Twenty five per cent of this energy is available for muscular work. If \(100 \mathrm{~kJ}\) of muscular work is needed to walk \(1 \mathrm{~km}\), what is the maximum distance that a person will be able to walk after eating \(120 \mathrm{~g}\) of glucose? (a) \(19.2 \mathrm{~km}\) (b) \(9.6 \mathrm{~km}\) (c) \(2.4 \mathrm{~km}\) (d) \(4.8 \mathrm{~km}\)
Problem 32
A geyser, operating on LPG (liquefied petroleum gas) heats water flowing at the rate of \(3.0\) litres per minutes, from \(27^{\circ} \mathrm{C}\) to \(77^{\circ} \mathrm{C}\). If the heat of combustion of LPG is \(40,000 \mathrm{~J} / \mathrm{g}\), how much fuel, in \(\mathrm{g}\), is consumed per minute? (Specific heat capacity of water is \(4200 \mathrm{~J} / \mathrm{kg}-\mathrm{K}\) ) (a) \(15.25\) (b) \(15.50\) (c) \(15.75\) (d) \(16.00\)
Problem 34
Equal volumes of one molar hydrochloric acid and one molar sulphuric acid are neutralized completely by dilute \(\mathrm{NaOH}\) solution by which \(X\) and \(Y\) kcal of heat are liberated, respectively. Which of the following is true? (a) \(X=Y\) (b) \(2 X=Y\) (c) \(X=2 Y\) (d) none of these
Problem 35
The reaction of zinc metal with hydrochloric acid was used to produce \(1.5\) moles of hydrogen gas at \(298 \mathrm{~K}\) and 1 atm pressure. The magnitude work done in pushing back the atmosphere is (a) \(596 \mathrm{cal}\) (b) \(894 \mathrm{cal}\) (c) \(447 \mathrm{cal}\) (d) \(298 \mathrm{cal}\)
Problem 38
The enthalpy of formation of \(\mathrm{KCl}(\mathrm{s})\) from the following data is (i) \(\mathrm{KOH}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{KCl}(\mathrm{aq})\) \(+\mathrm{H}_{2} \mathrm{O}(1) ; \Delta H=-13.7 \mathrm{kcal}\) (ii) \(\mathrm{H}_{2}(\mathrm{~g})+1 / 2 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) ; \Delta H\) \(=-68.4 \mathrm{kcal}\) (iii) \(1 / 2 \mathrm{H}_{2}(\mathrm{~g})+1 / 2 \mathrm{Cl}_{2}(\mathrm{~g})+\mathrm{aq} \rightarrow \mathrm{HCl}(\mathrm{aq})\) \(\Delta H=-39.3 \mathrm{kcal}\) (iv) \(\mathrm{K}(\mathrm{s})+1 / 2 \mathrm{O}_{2}(\mathrm{~g})+1 / 2 \mathrm{H}_{2}(\mathrm{~g})+\mathrm{aq}\) \(\rightarrow \mathrm{KOH}(\mathrm{aq}) ; \Delta H=-116.5 \mathrm{kcal}\) (v) \(\mathrm{KCl}(\mathrm{s})+\mathrm{aq} \rightarrow \mathrm{KCl}(\mathrm{aq}) ; \Delta H=+4.4 \mathrm{kcal}\) (a) \(+105.5 \mathrm{kcal} / \mathrm{mol}\) (b) \(-105.5 \mathrm{kcal} / \mathrm{mol}\) (c) \(-13.7 \mathrm{kcal} / \mathrm{mol}\) (d) \(-18.1 \mathrm{kcal} / \mathrm{mol}\)
Problem 39
Enthalpy of neutralization of \(\mathrm{H}_{3} \mathrm{PO}_{3}\) by \(\mathrm{NaOH}\) is \(-106.68 \mathrm{~kJ} / \mathrm{mol}\). If the enthalpy of neutralization of \(\mathrm{HCl}\) by \(\mathrm{NaOH}\) is \(-55.84 \mathrm{~kJ} / \mathrm{mol}\). The \(\Delta H_{\text {ionization }}\) of \(\mathrm{H}_{3} \mathrm{PO}_{3}\) into its ions is (a) \(50.84 \mathrm{~kJ} / \mathrm{mol}\) (b) \(5 \mathrm{~kJ} / \mathrm{mol}\) (c) \(10 \mathrm{~kJ} / \mathrm{mol}\) (d) \(2.5 \mathrm{~kJ} / \mathrm{mol}\)
Problem 41
The standard heat of combustion of propane is \(-2220.1 \mathrm{~kJ} / \mathrm{mol}\). The standard heat of vaporization of liquid water is \(44 \mathrm{~kJ} / \mathrm{mol}\). What is the \(\Delta H^{\text {o }}\) of the reaction: \(\mathrm{C}_{3} \mathrm{H}_{8}(\mathrm{~g})+5 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 3 \mathrm{CO}_{2}(\mathrm{~g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) ?\) (a) \(-2220.1 \mathrm{~kJ}\) (b) \(-2044.1 \mathrm{~kJ}\) (c) \(-2396.1 \mathrm{~kJ}\) (d) \(-2176.1 \mathrm{~kJ}\)
Problem 42
Calculate \(\Delta_{\mathrm{f}} H\) for \(\mathrm{ZnSO}_{4}(\mathrm{~s})\) from the following data: \(\mathrm{ZnS}(\mathrm{s}) \rightarrow \mathrm{Zn}(\mathrm{s})+\mathrm{S}\) (rhombic), \(\Delta H_{1}\) \(=44 \mathrm{kcal} / \mathrm{mol}\) \(2 \mathrm{ZnS}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{ZnO}(\mathrm{s})+2 \mathrm{SO}_{2}(\mathrm{~g})\) \(\Delta H_{2}=-221.88 \mathrm{kcal} / \mathrm{mol}\) \(2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{SO}_{3}(\mathrm{~g}), \quad \Delta H_{3}\) \(=-46.88 \mathrm{kcal} / \mathrm{mol}\) \(\mathrm{ZnSO}_{4}(\mathrm{~s}) \rightarrow \mathrm{ZnO}(\mathrm{s})+\mathrm{SO}_{3}(\mathrm{~g}), \Delta H_{4}\) \(=55.1 \mathrm{kcal} / \mathrm{mol}\) (a) \(-233.48 \mathrm{kcal} / \mathrm{mol}\) (b) \(-343.48 \mathrm{kcal} / \mathrm{mol}\) (c) \(-434.84 \mathrm{kcal} / \mathrm{mol}\) (d) \(-311.53 \mathrm{kcal} / \mathrm{mol}\)
Problem 43
The value of \(\Delta H_{\text {sol }}\) of anhydrous \(\begin{array}{lllll}\text { copper (II) sulphate } & \text { is } & -66.11 & \mathrm{~kJ}\end{array}\) Dissolution of 1 mole of blue vitriol, [Copper (II) sulphate pentahydrate] is followed by absorption of \(11.5 \mathrm{~kJ}\) of heat. The enthalpy of dehydration of blue vitriol is (a) \(-77.61 \mathrm{~kJ}\) (b) \(+77.61 \mathrm{~kJ}\) (c) \(-54.61 \mathrm{~kJ}\) (d) \(+54.61 \mathrm{~kJ}\)
Problem 45
Study the following thermochemical data: \(\mathrm{S}+\mathrm{O}_{2} \rightarrow \mathrm{SO}_{2} ; \quad \Delta H=-298.2 \mathrm{~kJ}\) \(\mathrm{SO}_{2}+1 / 2 \mathrm{O}_{2} \rightarrow \mathrm{SO}_{3} ; \quad \Delta H=-98.2 \mathrm{~kJ}\) \(\mathrm{SO}_{3}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{H}_{2} \mathrm{SO}_{4} ; \quad \Delta H=-130.2 \mathrm{~kJ}\) \(\mathrm{H}_{2}+1 / 2 \mathrm{O}_{2} \rightarrow \mathrm{H}_{2} \mathrm{O} ; \quad \Delta H=-287.3 \mathrm{~kJ}\) The enthalpy of formation of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) at \(298 \mathrm{~K}\) will be (a) \(-433.7 \mathrm{k} \mathrm{J}\) (b) \(-650.3 \mathrm{~kJ}\) (c) \(+320.5 \mathrm{~kJ}\) (d) \(-813.9 \mathrm{~kJ}\)
