51. use data from appendix iib to calculate srxn for each of the reactions. in each case, try to rationalize the sign of srxn . a. c2h4(g) + h2(g)

a polar bond is formed when electrons are shared unevenly between atoms

5 structural isomers

the isomers are:

n-exane :   ch3ch2ch2ch2ch2ch3

2-methylpentane :   ch3ch(ch3)ch2ch2ch3

3-methylpentane :   ch3ch2ch(ch3)ch2ch3

2,3-dimethylbutane :   (ch3)2chch(ch3)2

2,2-dimethylbutane :   (ch3)3cch2ch3