Chapter 13 - Alkenes

Question 1

Define the term ‘stereoisomeris’

Answer 1

Stereoisomers have the same stuctural formula but a different arrangement in space

Question 2

Explain why alkenes can have E/Z isomeriss but alkanes cannot.

Answer 2

E/Z isomers occur because atoms cant rotate about the C=C double bond. Alkanes don’t have a double C=C bond therefore they can’t have E/Z isomerism.

Question 3

When do we use the Cahn-Ingold-Prelog Rules?

Answer 3

When deciding if an isomer is E/Z when we have 4 different groups around the double bond

Question 4

How would u use the Cahn-Ingold-Prelog Rules?

Answer 4

• first label carbons with the double bond as carbon 1 and carbon 2
• second, calculate the Atomic Number of the fist element directly bonded to the C=C. The atom with highest atomic number is given a higher piority

Question 5

What halogenation test for?

Answer 5

Its a test for unsaturation (double bond)

Question 6

What are the conditins and reagents for Hydrogenation?

Answer 6

H2 and Nickel Catalysts

Question 7

What are the conditins and reagents of Hydration of Alkenes?

Answer 7

Steam H2O, H3PO4 catalyst

Question 8

What are the environmental benefits and concerns of polymers?

Answer 8

Benefits of using waste polymers
• combusting them for heat energy (use as fuel)
• Feedstock recycling (can be converted back into crude oil like materials and then reused to make new polymers)

Concerns
• PVC can release harmful chemicals such as HCL when combusted
• Waste polymers can wrap around marine life,suffocating them