Chemistry Question Bank

For vaporization of water at 1 atmospheric pressure, the values of ∆H and ∆S are 40.63 kJ mol–1 and 108.8 J K–1 mol–1, respectively. The temperature when Gibbs’ energy change (∆G) for this transformation will be zero,…

The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0°C is (2012)

For a given reaction, ∆H = 35.5 kJ mol–1 and ∆S = 83.6 J K–1 mol–1. The reaction is spontaneous at (Assume that ∆H and ∆S do not vary with temperature.) (NEET 2017)

Consider the following reaction –1 (aq) (aq) (l) –1 2(g) 2(g) (l) 2(g) 2(g) (g) (l) –1 2(g) 2(g) 2(g) (l) –1 (i)H OH H O , H X kJ mol (ii)H 1/ 2O H O , H X kJ mol (iii)CO H CO H O , H X kJ mol (iv)C H 5 / 2O 2CO H O ,…

Assume each reaction is carried out in an open container. For which reaction will H = E ? (CBSE AIPMT 2006) (a) H (g) Br (g) 2HBr(g) → (b) C(s) 2H O(g) 2H (g) CO (g) → (c) PCl (g) PCl (g) Cl (g) → (d) 2CO(g) O (g) 2CO…

Given that bond energies of H – H and Cl – Cl are 430 kJ mol–1 and 240 kJ mol–1 respectively and f H for HCl is-90 kJ mol–1 bond enthalpy of HCl is (2007)

If the bond energies of H–H, Br–Br, and H–Br are 433, 192 and 364 kJ mol–1 respectively, the H for the reaction 2(g) 2(g) (g) H Br 2HBr → is (2004)

The heat of formation of Fe O s is –824.2 kJ mol–1. ∆H for the reaction. 2Fe O s 4Fe s 3O g → is:

H for the reaction, C(graphite) 2H (g) CH (g) → at 298 K and 1 atm is – 17900 cal.  The E for the above conversion would be

The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm–3, respectively. The standard free energy difference ( G ) is equal to 1895 J mol–1, the pressure at which graphite will be transformed into diamon…

For the gas phase reaction, 5(g) 3(g) 2(g) PCl PCl Cl Which of the following conditions are correct? (2008)

The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm–3, respectively. If the standard free energy difference is equal to 1895 J mol–1, the pressure at which graphite will be transformed into diamond a…

105. (∆U – ∆H) for the formation of NH₃ from N₂ and H₂ is :

The standard enthalpies of formation of HCl(g), H  (g) and  Cl₂(g)  are  –92.2,  217.7  and  121.4  kJ  mol-1 respectively. The bond dissociation energy of HCl is:

The molar heat capacity of water at constant pressure, C, is 75J K-1. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is. (2003)

The absolute enthalpy of neutralisation of the reaction: (g) (g) 2(aq) (l) MgO 2HCl MgCl H O → Will be (2005)

A reaction occurs spontaneously if (2005)

Identify the correct statement for change of Gibbs’ energy for a system system ( G ) at constant temperature and pressure. (2006)

The enthalpy and entropy change for the reaction: 2(l) 2(g) (g) Br Cl 2BrCl → are 30 kJ mol–1 and 105JK–1 mol–1 respectively. The temperature at which the reaction will be in equilibrium is (2006)

The following data is known about the melting of a compound AB. ∆H = 9.2 kJ mol–1. ∆S = 0.008 kJ K–1mol–1. Its melting point is :

Which of the following are not state functins? (I) q + w (II) Q (III) w (IV) H – TS (2009)

The heat liberated when 1.89 g of benzoic acid is burnt in a bomb calorimeter at 25 °C increases the temperature of 18.94 kg of water by 0.632 °C. If the specific heat of water at 25 °C is 0.998 cal/g-deg, the value o…

The following two reactions are known Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g); ∆H = –26.8 kJ FeO(s) + CO(g) → Fe(s) + CO₂(g); ∆H = – 16.5 kJ The value of ∆H for the following reaction Fe₂O₃(s) + CO(g) → 2FeO(s) + CO₂(g) …

Enthalpy change for the reaction, 4H(g) 2H (g) → is – 869.6 kJ. The dissociation energy of H–H bond is (CBSE AIPMT 2011)

For the reaction, 2H O g 2H g O g → ∆H = 571.6 KJ fH of water is :