Organic Chemistry - A level

Question 1

Define a hydrocarbon.

Answer 1

A hydrocarbon is a compound containing carbon and hydrogen only.

Question 2

Define the phrase: functional group.

Answer 2

A functional group is an atom or group of atoms that determine the properties (physical and chemical) and characteristics of a compound.

Question 3

What is a Homologous series and its characteristics, in 4 points?

Answer 3

A homologous series is a group of compounds with:
1. the same general formula
2. the same chemical properties
3. the same functional group
4. gradually changing physical properties from member to member
5. a difference between members of a -CH₂- unit

Question 4

What is a Molecular Formula?

Answer 4

This is a formula showing the exact number of atoms in a compound.

Question 5

What is an Empirical Formula?

Answer 5

An empirical formula is the simplest whole number ratio of atoms in a compound.

Question 6

What is a displayed formula?

Answer 6

A displayed formula is one that shows the spatial arrangement of compounds in space.

Question 7

What is a skeletal formula?

Answer 7

A skeletal formula is a shorthand representation of the bonds in a compound.

It does not show a Carbon and its Hydrogens, showing only other paired atoms.

Question 8

How many bonds can carbon form?

Answer 8

Carbon can form 4 bonds.

Each bond is represented by a line.

Question 9

What is the reason why Carbon can make so many bonds?

Answer 9

Carbon is capable of making so many bonds because it forms stable, strong bonds.

Question 10

What is the general formula for Alkanes?

Answer 10

The general formula for alkanes is:
CₙH₂ₙ₊₂

Question 11

What is the functional group for Alkanes?

Answer 11

The functional group for alkanes is C-C

Question 12

What is the general formula for Alkenes?

Answer 12

The general formula for alkenes is:
CₙH₂ₙ

Question 13

What is the functional group for Alkenes?

Answer 13

The functional group for alkenes is:
C=C

Question 14

What is the general formula for Halogenoalkanes?

Answer 14

The general formula for halogenoalkanes is:
CₙH₂ₙ₊₁X

The X is a halogen, eg. F, Cl, Br, I

Question 15

What is the functional group for halogenoalkanes?

Answer 15

The functional group for halogenoalkanes is:
C-X

The chain of carbons can also be represented by R, making it R-X.

The X is a halogen, eg. F, Cl, Br, I

Question 16

What is the general formula for Alcohols?

Answer 16

The general formula for Alcohols is CₙH₂ₙ₊₁OH

Question 17

What is the functional group for Alcohols?

Answer 17

The functional group for alcohols is:
R-OH

Here, R, represents a string of carbons.

Question 18

What is the general formula for Aldehydes?

Answer 18

The general formula for aldehydes is:
CₙH₂ₙ₊₁CHO

There is a double bond between C and O and a single bond between C and H. An aldehyde’s structure is different from that of a Carboxylic acid in the lack of an H connected to the O.

Question 19

What is the functional group for the aldehyde homologous series?

Answer 19

The functional group for aldehydes is:
R-CHO

R represents a string of carbons of any number.

There is a double bond between C and O and a single bond between C and H. An aldehyde’s structure is different from that of a Carboxylic acid in the lack of an H connected to the O.

Question 19

What is the general formula for Ketones?

Answer 19

The general formula for Ketones is:
CₙH₂ₙ₊₁COCₙH₂ₙ₊₁

C=O is a pi bond.

A ketone is merely a chain of carbons with a singular oxygen paired to a carbon in the middle of the chain. It cannot be at the end because in that case there would be a hydrogen paired to the last Carbon, making it an aldehyde.

Question 20

What is the functional group for Ketones?

Answer 20

The functional group for Ketones is:
R-CO-R

C=O is a pi bond.
R represents a chain of carbons of any number.

A ketone is merely a chain of carbons with a singular oxygen paired to a carbon in the middle of the chain. It cannot be at the end because in that case there would be a hydrogen paired to the last Carbon, making it an aldehyde.

Question 21

What is the functional group for Carboxylic Acids?

Answer 21

The functional group for Carboxylic Acids is:
R-COOH

R represents a string of carbons of any number.

There is a double bond between C and one O, and a single bond with the other O, wich connects to an H.

Question 22

What is the general formula for Carboxylic Acids?

Answer 22

The general formula for Carboxylic Acids is:
CₙH₂ₙ₊₁COOH

There is a double bond between C and one O, and a single bond with the other O, wich connects to an H.

Question 23

What is the general formula for Nitriles?

Answer 23

The general formula for Nitriles is:
CₙH₂ₙ₊₁CN

There is a triple bond between C and N.

Question 24

What is the functional group for Nitriles?

Answer 24

The functional group for Nitriles is: **R-C≡N** ## Footnote R represents a string of carbons of any number.

Question 25

What is the functional group for Amines?

Answer 25

The functional group for Amines is **R-NH₂**.

Question 26

What is the general formula for Amines?

Answer 26

The general formula for Amines is: **CₙH₂ₙ₊₁NH₂**

Question 27

What is the general formula for the homologous group of Esters?

Answer 27

The general formula for the homologous group of Esters is: **CₙH₂ₙ₊₁COO**

Question 28

What is the functional group for the homologous group of Esters?

Answer 28

The functional group for the homologous group of Esters is: either **R-OCO-R** or **R-COO-R** ## Footnote There is a double bond between C and one O, and a single bond with the other O. The single bond O, connects to another Carbon.

Question 29

What are the 2 sorts of Hydrocarbons?

Answer 29

The 2 types of Hydrocarbons are: 1. Aliphatic Hydrocarbons 2. Aromatic Hydrocarbons

Question 30

What are Aliphatic hydrocarbons?

Answer 30

Aliphatic hydrocarbons are straight chained, cyclic, and branched compounds without a benzene ring.

Question 31

What are Aromatic hydrocarbons?

Answer 31

These are hydrocarbons containing a benzene ring.

Question 32

How do Aromatic hydrocarbons differ from Aliphatic hydrocarbons?

Answer 32

Aromatic hydrocarbons differ from Aliphatic hydrocarbons in that they contain a benzene ring.

Question 33

What is a General Formula?

Answer 33

A General Formula is a formula that represents a homologus series of compounds using letters and numbers.

Question 34

What is a saturated hydrocarbon?

Answer 34

A saturated hydrocarbon is a hydrocarbon that contains only C-C single bonds. ## Footnote An example of these is alkanes. As a result, Alkanes are inert, because the carbons within them each have their 4 bond possibilities fulfilled.

Question 35

What are the two sources of Alkanes?

Answer 35

The two sources of Alkanes are: 1. Fractional distillation of crude oil 2. Hydrogenation of alkenes

Question 36

Although alkanes are unreactive, they can participate in 3 reactions. What are these?

Answer 36

The 3 reactions alkanes can be involved in are: 1. burning in oxygen (combustion) 2. being broken down into smaller molecules through the process of cracking 3. reacting with halogens in free radical substitution reactions

Question 37

What is the prefix used for an organic compound with only 1 carbons?

Answer 37

The prefix **meth-** is used when an organic compound has only 1 carbon.

Question 38

What is the prefix used for an organic compound with only 2 carbons?

Answer 38

The prefix **eth-** is used when an organic compound has only 2 carbons.

Question 39

What is the prefix used for an organic compound with only 3 carbons?

Answer 39

The prefix **prop-** is used when an organic compound has only 3 carbons.

Question 40

What is the prefix used for an organic compound with only 4 carbons?

Answer 40

he prefix **but-** is used when an organic compound has only 4 carbons.

Question 41

What is the prefix used for an organic compound with only 5 carbons?

Answer 41

The prefix **pent-** is used when an organic compound has only 5 carbons.

Question 42

What is the prefix used for an organic compound with only 6 carbons?

Answer 42

The prefix **hex-** is used when an organic compound has only 6 carbons.

Question 43

What is the prefix used for an organic compound with only 7 carbons?

Answer 43

The prefix **hept-** is used when an organic compound has only 7 carbons.

Question 44

What is the prefix used for an organic compound with only 8 carbons?

Answer 44

The prefix **oct-** is used when an organic compound has only 8 carbons.

Question 45

What is the prefix used for an organic compound with only 9 carbons?

Answer 45

The prefix **non-** is used when an organic compound has only 9 carbons.

Question 46

What is the prefix used for an organic compound with only 10 carbons?

Answer 46

The prefix **dec-** is used when an organic compound has only 10 carbons.

Question 47

Define an addition reaction.

Answer 47

An **addition reaction** is a reaction in which two or more molecules react to form one product.

Question 48

What is Elimination?

Answer 48

Elimination is a reaction in which a small molecule is removed.

Question 49

Define Substitution.

Answer 49

Substitution is a reaction in which an atom or group of atoms is replaced by another.

Question 50

# Remember **OIL RIG** Explain what Oxidation is, in 3 separate points?

Answer 50

Oxidation is: 1. the addition of oxygen 2. loss of hydrogen 3. loss of electrons ## Footnote It is loss of all else (i.e. Hydrogen and electrons) except Oxygen itself.

Question 51

# Remember **OIL RIG** What is Reduction, explained in 3 separate points?

Answer 51

Reduction is: 1. the removal of oxygen 2. the addition of hydrogen 3. the gaining of electrons ## Footnote It is the opposite of oxidation.

Question 52

Explain the term: Free Radical Substitution

Answer 52

Free Radical Substitution is a reaction in which a radical replaces a hydgrogen from an alkane.

Question 53

What are the names of the 3 steps of Free Radical Substitution?

Answer 53

1. Step 1 is **Initiation** 2. Step 2 is **Propagation** 3. Step 3 is **Termination**

Question 54

Define a radical.

Answer 54

A radical is a molecule with an unpaired electron.

Question 55

What is Homolytic Fission?

Answer 55

Homolytic Fission is the breaking down of a covalent compound , such that each takes one electron. ## Footnote This produces free radicals, which are atoms or molecules with an unpaired electron, having had the other one taken. in this case unpaired refers to the lack of a partner in the orbital in which it resides.

Question 56

Explain what happens in Step 1 of Free Radical Substitution: Initiation.

Answer 56

Step 1, initiation, involves the formation of radicals, through the process of homolytic fission. | This is Step 1 in Free Radical Substitution. ## Footnote Homolytic Fission is the breaking down of a covalent compound , such that each takes one electron.

Question 57

Explain what happens in Step 2 of Free Radical Substitution: Propagation.

Answer 57

In Step 2, which is propagation, a radical reacts with a neutral molecule to form another radical and a neutral molecule. ## Footnote This is Step 2 in Free Radical Substitution.

Question 58

Explain what happens in Step 3 of Free Radical Substitution: Termination.

Answer 58

Termination, step 3 of Free Radical Substitution, is when two radicals combine to form one neutral molecule.

Question 59

Define Heterolytic fission.

Answer 59

Heterolytic fission is when a molecule breaks up and one molecule takes both electrons. ## Footnote This is due to the molecule being more electronegative than its counterpart. The reaction is shown using a curly arrow, illustrating the forcible taking of electrons.

Question 60

Describe what a Nucleophile is.

Answer 60

A Nucleophile is a species that contains a lone pair of electrons which it can donate. | Lone pairs of electrons are merely those that are not involved in a covalent bond. ## Footnote As a result, it attracts lone nuclei, like H+, making it a nucleus loving molecule, hence, nucleophile. Lone pairs of electrons are merely those that are not involved in covalent bonding. A molecule may still have 8 outer shell electrons and still have lone pairs of electrons.

Question 61

What is an Electrophile?

Answer 61

An electrophile is a species that can accept a lone pair of electrons.

Question 62

What is a condensation reaction?

Answer 62

A condensation reaction is a reaction in which 2 or more substances combine, and a small molecule is removed. ## Footnote Unlike elimination, it involves at least 2 reactants.

Question 63

What are the 2 types of Isomerism?

Answer 63

The two types of isomerism are: 1. Structural Isomerism 2. Stereoisomerism

Question 64

What are the 3 types of Structural Isomerism?

Answer 64

The three types of structural isomerism are: 1. Position isomerism 2. Functional Group Isomerism 3. Chain Isomerism

Question 65

What are the two divisions of Stereoisomerism?

Answer 65

The two divisions of Stereoisomerism are: 1. Geometric Isomerism 2. Optical Isomerism ## Footnote Geometric is further split into two parts; Cis and Trans.

Question 66

What is an unsaturated hydrocarbon?

Answer 66

An unsaturated compound is a hydrocarbon with a C=C double bond.

Question 67

Briefly explain Functional group structural isomerism.

Answer 67

Functional Group Structural isomerism occurs when two organic compounds have the same numbers of atoms but different functional groups. ## Footnote An example being butanol, CH₃CH₂CH₃CHO and butanone, CH₃COCH₂CH₃

Question 68

Briefly explain Position Structural Isomerism.

Answer 68

Position Structural Isomerism occurs when organic compounds have the same molecular formula, but different positons of the functional group. ## Footnote e.g. 1-bromobutane and 2-bromobutane

Question 69

Briefly explain Chain Structural Isomerism.

Answer 69

Chain Structural Isomerism occurs when organic compounds have the same molecular formula but differ in the longest chain in the compound.

Question 70

What is Stereoisomerism?

Answer 70

Stereoisomerism occurs when compounds have the same molecular formula but different orientations in space ## Footnote This occurs on a more 3 dimensional level.

Question 71

What are the conditions required for a compound to have a Geometric Stereoisomer?

Answer 71

For a compound to have a Geometric Stereoisomer, it must: 1. Have a double bond 2. Have each C connected to 2 differect groups or atoms

Question 72

Geometric Isomerism is split into Cis and Trans geometrical isomerism. Define each.

Answer 72

Cis Geometrical Isomerism, occurs when two similar groups, are on the same side of the double bond {both above or both below}. Trans Geometric isomerism occurs when two similar groups, or effectual groups are on either side of the double bond {that is above as well as below}

Question 73

What is a chiral carbon?

Answer 73

This is a carbon, in geometric isomerism, that is bonded to 4 different atoms or groups. ## Footnote It is labellled with an asterisk. It cannot have a double bond, otherwise the connected groups will only be 3.

Question 74

Why does Geometric Isomerism occur in alkenes?

Answer 74

Geometric Isomerism occurs in alkenes due to restricted rotation in alkenes as a result of the double bonds ## Footnote As compared to the free rotation of Alkanes, which cannot experience Geometric Isomerism.