Use the bond energies provided to estimate ΔH°ᵣₓₙ for the reaction below.

2 Br2 (l) + C2H2 (g) → C2H2Br4 (l)

Br-Br = 193 kJ/mol; C≡C = 837 kJ/mol; C-C = 347 kJ/mol; C-Br = 276 kJ/mol;

C-H = 414 kJ/mol

a) + 407 kJ b) - 228 kJ c) + 573 kJ d) - 648 kJ e) - 324 kJ

Question

Chemistry

Leonel Wyatt

24 November, 16:14

Use the bond energies provided to estimate ΔH°ᵣₓₙ for the reaction below.

2 Br2 (l) + C2H2 (g) → C2H2Br4 (l)

Br-Br = 193 kJ/mol; C≡C = 837 kJ/mol; C-C = 347 kJ/mol; C-Br = 276 kJ/mol;

C-H = 414 kJ/mol

a) + 407 kJ b) - 228 kJ c) + 573 kJ d) - 648 kJ e) - 324 kJ

+5

Answers (1)

Know the Answer?

Ada Jordan · Answer 1

The answer is b), - 228 kJ

Explanation:

First, we consider which bonds are broken and formed during the reaction

Broken, Br - Br (02 molecules), C ≡ C

Formed, C - C, C - Br (4 bonds)

Noted that when breaking bonds, the molecules NEED energy, while forming bond, they release energy. So, secondly, we calculate

Breaking energy = 2 x (Br-Br) + 1 x (C≡C) = 2 x 193 + 1 x 837 = 1,223 kJ

Forming energy = - (4 x (C-Br) + 1 x (C-C) = - (4 x 276 + 1 x 347) = - 1,451 kJ (minus means that the energy is released during the reaction)

Hence the ΔH°ᵣₓₙ is 1,223 kJ + (-1,451) kJ = - 228 kJ

Use the bond energies provided to estimate ΔH°ᵣₓₙ for the reaction below.2 Br2 (l) + C2H2 (g) → C2H2Br4 (l)Br-Br = 193 kJ/mol; C≡C = 837 kJ/mol; C-C = 347 kJ/mol; C-Br = 276 kJ/mol;C-H = 414 kJ/mola) + 407 kJ b) - 228 kJ c) + 573 kJ d) - 648 kJ e) - 324 kJ

Use the bond energies provided to estimate ΔH°ᵣₓₙ for the reaction below.

2 Br2 (l) + C2H2 (g) → C2H2Br4 (l)

Br-Br = 193 kJ/mol; C≡C = 837 kJ/mol; C-C = 347 kJ/mol; C-Br = 276 kJ/mol;

C-H = 414 kJ/mol

a) + 407 kJ b) - 228 kJ c) + 573 kJ d) - 648 kJ e) - 324 kJ