Midterm

Question 1

Which hybridization states of carbon is the lowest energy?

Answer 1

sp

Question 2

Which hybridization states of carbon is the highest energy?

Answer 2

sp^3

Question 3

Van der Waals forces are expected to be the strongest between _________ molecules
a) CH4 b) H2 c) Cl2 d) Br2

Answer 3

Br2

Question 4

The strongest Van der Waals forces of attraction exist between molecules of
a) I2 b) Br2 c) Cl2 d) F2

Answer 4

I2

Question 5

What is the pKa for H2O

Answer 5

15.7

Question 6

What is the IUPAC name for isobutane

Answer 6

2-methylpropane

Question 7

What is the approximate H-C-H bond angle in methane?

Answer 7

109

Question 8

How much is a gauche butane interaction worth?

Answer 8

0.9 kcal/mol

Question 9

What is the barrier to rotation of ethane?

Answer 9

3.0 kcal/mol

Question 10

What is the pKa of ethane?

Answer 10

50

Question 11

Which orbital has 25% s character? What is its pKa?

Answer 11

sp3; pKa=50

Question 12

Which orbital has 33% s character? What is its pKa?

Answer 12

sp2; pKa=43

Question 13

Which orbital has 50% s character? What is its pKa?

Answer 13

sp; pKa=25

Question 14

Order these from most electronegative to least electronegative:
sp, sp2, sp3

Answer 14

sp3, sp2, sp (sp is most sp3 is lease)

Question 15

What is the pKa for NH3?

Answer 15

33

Question 16

What is the torsional strain for a staggered, anticoplanar relative torsional strain?

Answer 16

0.0 kcal/mol

Question 17

What is the torsional strain for an eclipsed strain?

Answer 17

3.8 kcal/mol

Question 18

What is the torsional strain for a staggered, gauche strain?

Answer 18

0.9 kcal/mol

Question 19

What is the torsional strain for a eclipsed, syn-coplanar torsional strain?

Answer 19

4.5 kcal/mol (worst one)