Unsaturated compounds

Question 1

What is the difference between unsaturated and saturated compounds?

Answer 1

unsaturated

• have double bonds = sp2
• have pi bonds = unhybridised p orbitals
• more reactive = due to presence of pi bonds which are weaker than sigma bonds so are easily broken

saturated

• have single bonds = sp3
• only have sigma bonds = strong and more difficult to break than pi bonds

Question 2

What is hydrogenation?

Answer 2

reduction reaction
- reduces alkenes and alkynes into alkanes = gain of hydrogen

requires

• palladium or platinum catalyst
• solvent
• pressure

Question 3

What are oxidation and reduction reactions?

Answer 3

oxidation

• loss of electrons
• loss of hydrogen
• gain of oxygen

reduction

• gain of electrons
• gain of hydrogen
• loss of oxygen

Question 4

What are oxidising and reducing agents?

Answer 4

oxidising agent
- is reduced and oxidises the reactant

reducing agent
- is oxidised and reduces the reactant

Question 5

What are 
polymers?
polymerisation reactions?
addition polymer?
n?

Answer 5

polymers
- large molecules contain many identical repeating units

polymerisation reaction
- repetitive reaction which combines many small molecules of monomers to form a polymer

addition polymer
- polymer in which the monomers add together to form no other products but the polymer

n
- degree of polymerisation = number of monomers in the polymer chain

Question 6

What are alkynes?

Answer 6

have a triple bond

- linear = 180

Question 7

What is the order of reactivity of alkanes, alkenes and alkynes?

Answer 7

alkanes

• single bond = only sigma bonds
• least reactive = no pi bonds

alkenes

• double bonds = 1 sigma and 1 pi bond
• more reactive = have a pi bond

alkynes

• triple bonds = 1 sigma bond and 2 pi bonds
• most reactive = have pi bonds