Unit 2 Section 5 Mechanisms and Spectra

Question 0

What is an a polymerisation reaction?

Answer 0

Joining together lots of simple molecules to form a giant molecule.

Question 1

What is an addition reaction?

Answer 1

Joining 2 or more molecules together to form a larger molecule.

Question 2

What is an elimination reaction?

Answer 2

When a small group of atoms breaks away from a larger molecule.

Question 3

What is an substitution reaction?

Answer 3

When one species is replaced by another.

Question 4

What is an hydrolysis reaction?

Answer 4

Splitting a molecule into two new molecules by adding H⁺ and OH⁻ derived from water.

Question 5

What is an oxidation reaction?

Answer 5

Any reaction in which an atom loses electrons.

Question 6

What is an reduction reaction?

Answer 6

Any reaction in which an atoms gains electrons.

Question 7

What is a redox reaction?

Answer 7

Any reaction where electrons are transferred between two species.

Question 8

What do nucleophiles usually reactive with?

Answer 8

They donate electron pairs. They react with positive ions or polar bonds.

Question 9

What will free radicals react with?

Answer 9

Anything.

Question 10

What are the 2 ways that a covalent bond can break?

Answer 10

Heterocyclic and homolytic fission

Question 11

Explain heterolytic fission.

Answer 11

The bond breaks unevenly. Both electrons move to one atom. This will produce a cation (electrophile) and an anion(nucleophile). This is shown by drawing a full head arrow to one of the atoms from the bond.

Question 12

Explain homolytic fission.

Answer 12

The bond breaks evenly so each atom gains one electron. This gives 2 neutral free radicals.
This is shown by drawing half head arrows from the bond to each of the atoms.

Question 13

What is the basic of infra-red spectroscopy?

Answer 13

A range of infra red radiation is shown through an organic compound. Some of these will be absorbed.

Question 14

What is percentage transmittance?

Answer 14

How much of a frequency can get through an organic compound.

0% would mean all of it was absorbed.

Question 15

What happens to the bonds in a molecule when they go through infra-red spectroscopy?

Answer 15

They will absorb different wavelengths meaning they can vibrate to a higher level.
The energy involved depends on the bond length and the size of the atoms.

Question 16

What is the finger print region?

Answer 16

The area of a infra-red spectroscopy graph which is on the right. There are many different peaks and troughs and it is unique to each molecule.