Use enthalpies of formation given in appendix c to calculate δh for the reaction br2(g)→2br(g), and use this value to estimate the bond enthalpy d(br−br).

Given reaction represents dissociation of bromine gas to form bromine atoms

Br2(g) ↔ 2Br(g)

The enthalpy of the above reaction is given as:

ΔH = ∑n(products)Δ - ∑n(reactants)Δ

where n = number of moles

Δ= enthalpy of formation

ΔH = [2*ΔH(Br(g)) - ΔH(Br2(g))] = 2*111.9 - 30.9 = 192.9 kJ/mol

Thus, enthalpy of dissociation is the bond energy of Br-Br = 192.9 kJ/mol

So the formula of circumference is (diameter x Pi) or (2r x Pi).  

In this case, your diameter is 2 so your equation would be 2 x 3.14= 6.28 and rounded to the nearest tenth would your answer would be 6.30 inches.

Step-by-step explanation: