Question

calculate the heat of reaction \\( \delta h \\) for the following reaction:

\\( 2 \mathrm { hcl } ( g ) + \mathrm { br } _ { 2 } ( g ) \
ightarrow 2 \mathrm { hbr } ( g ) + \mathrm { cl } _ { 2 } ( g ) \\)

you can find a table of bond energies by using the data button on the aleks toolbar.

round your answer to the nearest \\( \mathrm { kj } / \mathrm { mol } \\).

\\( \frac { \mathrm { kj } } { \mathrm { mol } } \\)

Explanation:

Step1: List bond energies

Typical bond energies (kJ/mol): H-Cl=431, Br-Br=193, H-Br=366, Cl-Cl=242.

Step2: Calculate energy in

Energy to break bonds: $2×431 + 193 = 862 + 193 = 1055$ kJ/mol.

Step3: Calculate energy out

Energy released from forming bonds: $2×366 + 242 = 732 + 242 = 974$ kJ/mol.

Step4: Compute ΔH

$\Delta H = \text{energy in} - \text{energy out} = 1055 - 974 = 81$ kJ/mol.

Answer:

81