Chemistry Question Bank

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)

Three thermochemical equations are given below: (i) C(graphite) + O₂(g) → CO₂(g); ∆rH° = x kJ mol–1 (ii) C(graphite) + ½O₂(g) → CO(g); ∆rH° = y kJ mol–1 (iii) CO(g) + ½O₂(g) → CO₂(g); ∆rH° = z kJ mol–1 Based on the ab…

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)

Consider the following liquid-vapour equilibrium. Liquid ⇌ Vapour Which of the following relations is correct? (NEET-I 2016) (a) v H dln P dT T (b) v H d ln P dT RT (c) v H dln G dT RT (d) v H d ln P dT RT

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)

The bond dissociation energies of X2, Y₂ and XY are in the ratio of 1 : 0.5 : 1. ∆H for the formation of XY is – 200 kJ mol–1. The bond dissociation energy of X2 will be (NEET 2018)

In which case change in entropy is negative? (NEET 2019)

For the reaction, 2Cl(g) → Cl₂(g), the correct option is (NEET 2020)

A system undergoes a 3-step process. In step 1, 25 J of work is done by the system as its internal energy (U) decreases by 50 J. In step 2, w = -15J and q = +40J. In step 3 at constant volume, the system gives off 50 …

A system undergoes a 2-step process. In step 1, 15 J of work is done on the system as its internal energy increases by a total of 30 J. In step 2, at constant volume, the system decreases its internal energy by 20 J. …

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

The magnitudes of enthalpy changes for irreversible adiabatic expansion of a gas from 1L to 2L is H₁ and for reversible adiabatic expansion for the same expansion is H₂. Then

When 1 mol of an ideal gas is compressed to half of its volume, its temperature becomes double; then the change in entropy (S) would be:

Consider the reaction below at 298 K: C (graphite) + 2H₂ (g) → CH₄ (g) →fHº (kJ/mol) – 74.9 S₀ m(J/K/mol + 5.6 + 130.7 Which statement below is correct ?

For which of the following cases H S T ?

B. P G T 2. T C. P H S 3. -S D. H T P 4. P 5. V

Assertion: The extensive properties of a single pure substance will not only depend upon the number of moles of the substance present but also on any two of the three variables. Reason: Any extensive property if expre…

Assertion: There is no change in internal energy for an ideal gas at constant temperature. Reason: Internal energy of an ideal gas is a function of temperature only.

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…

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

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

Based on the first law of thermodynamics, which one of the following is correct?

In ….. process, work is done at the expense of internal energy.

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 :