Thermodynamics ...

Direction (Q. Nos. 1-13) This section contains 13 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.

Q. Thus, (BE) of bond in O₂ is

Δ_fH° of CS₂ = 117.36 kJ mol^-1

C(g) = 716.682 kJ mol^-1
S(g) = 278.805 kJ mol^-1 

Q. Thus, bond enthalpy in CS₂ is

The dissociation energy of CH₄ and C₂H₆ to convert them into gaseous atoms are 360 and 620 kcal mol^-1 respectively. Thus, bond energy of (C—C) bond is

The (C— Cl) bond energy of CCI₄ (l) can be derived from thermochemical data

Bond dissociation energy of = + 590 kJ mol^-1 and that of (C—C) = + 331 kJ mol^-1 at 298 K.

Enthalpy change for the polymerisation of ethene to polyethene is (where n is large integral value)

Given at 298 K

Q. The resonance energy of benzene is

Given the following thermochemical data at 298 K and 1 bar

ΔH°_vap (CH₃OH) = 38.0 kJ mol^-1
Δ_fH°: H(g) = 218 kJ mol^-1
O(g) = 249 kJ mol^-1
C(g) = 715 kJ mol^-1

Bond dissociation energy

(C—H) = 415 kJ mol^-1
(C—O) = 356 kJ mol^-1
(O—H) = 4 6 3 kJ mol^-1

Q. The Δ_fH° of liquid methyl alcohol in kJ mol^-1 is

Heat of hydrogenation of ethene is x₁ and that of benzene is x₂. The resonance energy of benzene is

Given, BE of = 498.8 kJ mol^-1
BE of (O—O) in ozone = 302.3 kJ mol^-1

Q. What is enthalpy change of the reaction

The standard enthalpies of formation of SF₆ (g), S (g)and F (g) are -1100, + 275 and + 80 kJ mol^-1. Thus, average bond energy of (S—F) in SF₆ is

Calculate resonance energy of N₂O from the following data

Δ_fH° (N₂O) = 82 kJ mol^-1

Given, Δ_fH° (H₂S) = 20.1 kJ mol^-1

Δ_fH° (H)(g) = +218.0 kJ mol^-1
Δ_fH° (S) (g) = +277.0 kJ mol^-1

and bond dissociation energy of first (H—S) bond in H₂S is 376.6 kJ mol^-1. Thus, Δ_fH° (HS)is

Given, BE (H—H) - x₁, BE = x₂, BE (O—H) = x₃ and for H₂O (l) → H₂O (g), ΔH = x₄ mol^-1, then Δ_fH° [H₂O (l)] is

Direction (Q. Nos. 14) Choice the correct combination of elements and column I and coloumn II  are given as option (a), (b), (c) and (d), out of which ONE option is correct.

Q. Given thermochemical data under standard states at 278 K and 1 bar.

Match the types of bonds in Column I with their respective value of bond-energy in Column II and select answer from the codes given below the table