Using the data provided, calculate the multiple bond energy ( kJ mol -1) of a C ≡ C bond in C 2 H 2. That energy is (take the bond energy of a C - H bond as 350 kJ mol -1) 2C (s) longrightarrow 2C (g) Δ H =1410 kJ mol -1 2C (s) longrightarrow 2C (g) Δ H =1410 kJ mol -1 H 2 (g) longrightarrow 2H (g) Δ H =330 kJ mol -1

Question

Using the data provided, calculate the multiple bond energy ( kJ mol -1) of a C ≡ C bond in C 2 H 2. That energy is (take the bond energy of a C - H bond as 350 kJ mol -1) 2C (s) longrightarrow 2C (g) Δ H =1410 kJ mol -1 2C (s) longrightarrow 2C (g) Δ H =1410 kJ mol -1 H 2 (g) longrightarrow 2H (g) Δ H =330 kJ mol -1 (A) 1165 (B) 837 (C) 865 (D) 815

Tardigrade Admin · Accepted Answer

(i) 2C (s)+ H 2(g) longrightarrow H - C ≡ C - H (g) Δ H =225 kJ mol -1 (ii) 2C (s) longrightarrow 2C (g) Δ H =1410 kJ mol -1 (iii) H 2(g) longrightarrow 2H (g) Δ H =330 kJ mol -1 From equation (i): 225=[2 × Δ H C ( s ) longrightarrow C ( g )+1 × BE H - H ]-[2 × BE C - H +1 × BE C = C ] 225=[1410+1 × 330]-[2 × 350+1 × BE C = C ] 225=[1410+330]-[700+ BE C = C ] 225=1740-700- BE C = C 225=1040- BE C = C BE CeC =1040-225=815 kJ mol -1

Q. Using the data provided, calculate the multiple bond energy (kJmol−1) of a C≡C bond in C2​H2​. That energy is (take the bond energy of a C−H bond as 350kJ mol −1) 2C(s)⟶2C(g)ΔH=1410kJ mol −1 2C(s)⟶2C(g)ΔH=1410kJ mol −1 H2​(g)⟶2H(g)ΔH=330kJ mol −1

1165

837

865

815