The reaction of cyanamide, NH₂CN_(s) with oxygen was run in a bomb calorimeter and $∆$U was found to be –742.24 kJ mol^–1. The magnitude of ${\mathrm{\Delta H}}_{298}$(KJ) for the given-below reaction is:

NH₂CN_(s) + \(\frac{3}{2}\)O_2(g) → N_2(g) + O_2(g) + H₂O_(l) 

[Assume ideal gases and \(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\)]$$

The average S–F bond energy in kJ mol^–1 of SF₆ is:

 [The values of standard enthalpy of formation of
SF₆(g), S(g), and F(g) are –1100, 275, and 80 kJmol^–1 respectively.]

The internal energy change (in kJ) when 90g of water undergoes complete evaporation at 100ºC is -

(Given : $∆$H_vap for water at 373 K = 41 kJ/mol, R = 8.314 JK^–1mol^–1)

1. 154.5

2. 168.5

3. 176.5

4. 189.5

For one mole of an ideal gas, which of these statements must be true?
(I) U and H each depend only on temperature.
(II) Compressibility factor z is not equal to 1.
(III) C_{P, m} – C_{V, m} = R
(IV) dU = C_VdT for any process.
1. (I), (III) and (IV)
2. (II), (III) and (IV)
3. (III) and (IV)
4. (I) and (III)

Five moles of an ideal gas at 1 bar and 298 K are expanded into a vacuum till the volume doubles. The work done is:
1. –RT ln V₂/V₁
2. C_V(T₂ – T₁)
3. zero
4. – RT(V₂ – V₁)

Lattice energy and enthalpy of the solution of NaCl are 788 kJ mol^–1 and 4 kJ mol^–1 , respectively. The hydration enthalpy of NaCl is:
1. –780 kJ mol^–1
2. –784 kJ mol^–1
3. 780 kJ mol^–1
4.  784 kJ mol^–1

If, for a dimerization reaction, 2A_(g) → A_2(g)  at   298 K , ∆U^Θ = -20 kJ mol^-1   ∆S^Θ   = - 30 J K^-1mol^-1 , then ∆G^Θ  will be:

1. -10. 4 kJ

2. 18.9 kJ

3. -13.5 kJ

4. 17. 4 kJ

Which one of the following equations does not correctly represent the first law of thermodynamics for the given processes involving an ideal gas? (Assume non-expansion work is zero)
1. Adiabatic process : $∆U = -w$
2. Cyclic process: $q = -w$
3. Isothermal process: $q = -w$
4. Isochoric process: $∆U = q$