Chemistry Question Bank

One mole of an ideal gas expands reversibly and adiabatically from a temperature of 27°C. If the work done during the process is 3 kJ, then final temperature of the gas is:(CV = 20 J/K)

Which of the following expressions regarding entropy is not correct? (a) system q S T (b) system total surrounding S S S (c) final initial S S S (d) total system surrounding S S S

Read the following statements regarding spontaneity of a process and mark the appropriate choice. (i)   When enthalpy factor is absent then randomness factor decides spontaneity of a process. (ii) When randomness fact…

In which case change in entropy is negative?

The entropy change when two moles of ideal monoatomic gas is heated from 200°C to 300°C reversibly and isochorically?

One mole of an ideal diatomic gas (Cv = 5 cal) was transformed from initial 25°C and 1 L to the state when temperature is 100°C and volume 10 L. The entropy change of the process can be expressed as (R = 2 calories/mo…

A reaction has ∆H = – 33 kJ and ∆S = +58 J/K. This reaction would be :

Which one of the following is correct? (a) G H T S

For the gas phase reaction, PCl g PCl g Cl g Which of the following conditions are correct?

2 moles of ideal gas at 27°C temperature is expanded reversibly from 2 lit. to 20 lit. find entropy change. (R = 2 cal/mol K)

In which of the following cases, the reaction is spontaneous at all temperatures ?

H and E  for the reaction, Fe O s 3H g 2Fe s H O l → at constant temperature are related as (a) H E (b) H E RT (c) H E RT (d) H E 3RT

The enthalpy of vaporisation of a compound AB at its boiling point (127°C) is 6.4 kJ mol-1. Its entropy of vaporization 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…

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

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:

For the reaction, 8 g 2 g 2 g l C H 5O 3CO 4H O → at constant temperature, H E is (2003)

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…

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

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)

From the following bond energies: H — H bond energy : 431.37 kJ mol–1 C == C bond energy : 606.10 kJ mol–1 C — C bond energy : 336.49 kJ mol–1 C — H bond energy : 410.50 kJ mol–1 Enthalpy for the reaction, will be (2009)

For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, U and w correspond to