DF lmhij: Organic functional groups & nomenclature; catalysis; cracking

Question 1

Why does carbon bond covalently, rather than ionically?

Answer 1

• In group 4 so would form +4 or -4 ions
• Too highly charged to be stable
• Covalent bonding is stabler

Question 2

Define catenation.

Answer 2

The covalent bonding of atoms of the same element into a series (chain/ring).

Question 3

What are functional groups?

Answer 3

Modifiers responsible for the reactionary properties of molecules.

Question 4

What are:

1. aromatic compounds?
2. arenes?
3. aliphatic hydrocarbons?

Answer 4

1. Molecules containing planar (flat) rings with delocalised electrons
2. Hydrocarbons containing benzene
3. Hydrocarbons based on chains of carbon atoms

• Benzene is aromatic but is not the only aromatic compound*
• All arenes are aromatic, but the reverse is untrue*

Question 5

Give the molecular formula of benzene.

Answer 5

C₆H₆

Question 6

What is a homologous series?

Answer 6

A family of hydrocarbons which share the same general formula.

Same functional groups; U_n differs from U_n+1 by -CH₂

Question 7

What is the general formula of an alkyl group?

Answer 7

C_nH_{2n + 1}​

Question 8

The common name for a compound is PVC, but its ___ name is polychloroethene.

Answer 8

systematic

Question 9

Give the shortened structural formula of ethane.

Answer 9

CH₃-CH₃

CH₃CH₃

Question 10

Give the electronic configuration of:

• the ground state of carbon
• its hybrid orbital (which is how you almost always encounter it)

Answer 10

1s²2s²2p² → 1s²2s¹2p³

Question 11

What is the general formula of cycloalkanes?

Answer 11

C_nH_2n

Question 12

Define:

• Saturated hydrocarbons
• Unsaturated hydrocarbons

Answer 12

• Ones containing no C=C or C≡C bonds; maximum possible number of hydrogen atoms
• Ones containing C=C and/or C≡C bonds; non-maximum possible number of hydrogen atoms

Question 13

Name C₂H₅CH₂(CH₂)CH₂(C₂H₅)C₂H₅

Answer 13

3-ethyl-4-methyl-hexane

Keep numbers as low as possible but also list side chains alphabetically.

Question 14

Name CH₂-C-CH-C₂H₅

Answer 14

Penta-1,2-diene

Don’t forget the a

Question 15

Define cracking.

Answer 15

A reaction in which a larger molecule is turned into smaller ones.

Question 16

1. What is a catalyst?
2. Define catalysis

Answer 16

• A substance which increases the rate of a reaction, by providing an alternative pathway with a lower activation energy, but which remains chemically unchanged.
• The process of speeding up a chemical reaction using a catalyst.

Question 17

What is homogeneous catalysis?

Answer 17

Catalysis in which the reactants and catalyst are in the same physical state.

Question 18

What is heterogeneous catalysis?

Answer 18

Catalysis in which the reactants and catalyst are in different physical states.

Usually involves gases and/or liquids reacting in presence of solid catalyst

Question 19

Describe the process of heterogeneous catalysis, where the catalyst is a solid surface.

Answer 19

• Reactants adsorbed onto catalyst surface
• Bonds in reactants weaken then break
• New bonds form between reactants
• This weakens then breaks bonds to catalyst surface
• Products released

Question 20

What is a catalyst poison?

Answer 20

A substance that stops a catalyst functioning properly.