Question

“Cyclobutene” is a highly strained ring, caused by the sp³ and sp² carbon atoms forced to form 90^o bond angles. Look up the standard enthalpy of formation of cyclobutene in the HSC database. Given the following bond energy values: C(s)→C(g) +717, H−H +436, C−C 347, C−H    414 kJ/mol:

1-Write the formation reaction for cyclobutene(g)

2- Calculate the estimated standard enthalpy of formation of cyclobutene(g) using Bond Energy values.

3- Calculate the estimated “ring strain” in cylobutene.

4- Schematically draw an enthalpy diagram showing the measured and BE estimated values of the standard enthalpy of formation, and with an arrow indicate the “ring strain” in the enthalpy diagram. (Note: ring strains are always positive).

5- Comment on your results.

I looked up the standard enthalpy of formation of cyclobutene in the HSC database: 156.7 Kj/mol..please help

Answer 1