CHM 2201 Chapter 6 Sample Exam Answers

 

Chapter 6: Alkenes: Structure and Reactivity

 

Part A: Degree of Unsaturation 10 Points

 

Calculate the degree of unsaturation for the following formulas. For one or two problems below show variations with suggested isomer structures:

(1)  C40H56 (β-carotene) 40x2+2=82 56(H) = 26/2= 13 degrees of unsaturation

 

(2)  C4H6 4x2+2=10 6(H) = 4/2= 2 degrees of unsaturation

 

 

(3)  C6H5N 6x2+2=14 5(H) = 9 1 (for N) = 8/2 = 4 degrees of unsaturation

 

 

 

(4)  C6H5NO2 (oxygens are not double bonded)

6x2+2=12 5(H) = 7 1 (for N) = 6/2 (ignore oxygen) = 3 degrees of unsaturation

 

 

(5)  C8H9Cl3 8x2+2=18 [9(H) + 3 (for Cl)] = 6/2 = 3 degrees of unsaturation

 

 

 

(6)  C5H6 5x2+2=12 6(H) = 6/2= 3 degrees of unsaturation

 

 

 

(7)  C9H16Br2 9x2+2=20 [16(H) + 2 (for Br)] = 2/2 = 1 degree of unsaturation

 

 

 

(8)  C20H32ClN 20x2+2=42 [32(H) + 1 (for Cl)] = 9 1(for N) = 8/2 = 4 degrees of unsaturation

 

 

 

(9)  C3H4 3x2+2=8 4(H) = 4/2= 2 degrees of unsaturation

 

 

 

(10) C6H9N 6x2+2=14 9(H) = 5 1 (for N) = 4/2 = 2 degrees of unsaturation