Chemistry Question Bank

G T S  when H

If the enthalpy change for the transition of liquid water to steam is 30 kJ mol–1 at 27°C, the entropy change for the process would be (2011)

For a sample of perfect gas when its pressure is changed isothermally from pi to pf, the entropy change is given by. (NEET-II 2016)

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

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)

A reaction occurs spontaneously if (2005)

∆H for the reaction, SO g O g SO g ∆H = –98.3 kJ If the enthalpy of formation of SO₃(g) is –395.4 kJ then the enthalpy of formation of SO₂(g) is :

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:

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…

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 :

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

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

When 0.5 g of sulphur is burnt to SO₂ 4.6 kJ of heat is liberated. What is the enthalpy of formation of sulphurdioxide?

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 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:

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 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…

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)

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 ,…

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

Bond dissociation enthalpy of H₂ Cl₂, and HCl are 434, 242 and 431 kJ mol respectively. Enthalpy of formation of HCl is (2008)

The values of H and S for the reaction, (graphite) 2(g) (g) C CO 2CO → Are 170 kJ and 170 JK–1, respectively. This reaction will be spontaneous at (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…

Standard entropies of X2, Y₂ and XY₃ are 60, 40 and 50 J K–1 mol–1 respectively. For the reaction 1/2X2 + 3/2Y₂ ⇌ XY₃, ∆H = –30 kJ, to be at equilibrium, the temperature should be (2010)

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…