Module 4 Chapter 11

Question 1

Why is carbon the basis for all organic molecules (1)

Answer 1

Carbons easily form chains and rings because they form strong bonds with other carbon atoms.

Question 2

Why is carbon the basis for all organic molecules (2)

Answer 2

They also form covalent bonds with atoms of other elements such as oxygen, nitrogen, hydrogen and the halogens

Question 3

Why is carbon the basis for all organic molecules (3)

Answer 3

Carbon atoms form four links with other atoms. And this allows more atoms to be attached to the chains and rings so that the branches and other groups can be added.

Question 4

What types of bonds can carbon form

Answer 4

Carbon atoms can form single, double or triple bonds.

Question 5

How many electrons are involved in the 3 different types of covalent bonds

Answer 5

One shared pair of electrons = single bond
Two shared pairs of electrons = double bond
Three shared pairs of electrons = triple bond

Question 6

What is the empirical formula

Answer 6

The simplest whole number ratio of the number of atoms in each element in a compound

Question 7

What is the molecular formula

Answer 7

The actual number of atoms of each element in a compound

Question 8

What is a displayed formula

Answer 8

Shows the order in which atoms are bonded (must show every bond). It also shows the relative positions of all atoms in a molecule and bonds between them.

Question 9

What is a structural formula

Answer 9

Shows the minimal detail that shows the arrangement of atoms in a molecule.

Question 10

What is skeletal formula

Answer 10

Shows a line for each bond but no carbon atoms or hydrogens next to carbons are shown. All other atoms are shown.

Question 11

What are hydrocarbons (and examples)

Answer 11

They are compounds containing carbon and hydrogen only. They include alkanes, cycloalkanes, alkenes and arenas.

Question 12

What does crude oil consist of

Answer 12

Crude oil consists of lots of hydrocarbons

Question 13

What are cycloalkanes

Answer 13

Are alkanes where the two ends are joined to make a ring

Question 14

What are Arenes

Answer 14

They are an organic molecule that contains one or more benzene ring in which 6 carbon atoms are joined in a ring.
Each carbon atom is only joined to three other atoms so each carbon has one outer shell electron left over.

Question 15

What do these delocalised electrons do

Answer 15

They are shared between all 6 carbon atoms to make a delocalised pool of electrons shown by the circle in the middle of the ring.

Question 16

What is a ring with delocalised electrons like this called

Answer 16

An aromatic ring

Question 17

What does a benzene ring look like

Answer 17

DRAW IT

Question 18

What is an aromatic compound

Answer 18

A compound containing a benzene ring

Question 19

What are aliphatic hydrocarbons

Answer 19

Containing carbon atoms joined together in unbranched (straight) or branched chains and are not aromatic

Question 20

What are alicyclic hydrocarbons

Answer 20

Contain carbon atoms joined together in a ring that is not aromatic

Question 21

What is a saturated hydrocarbon

Answer 21

A hydrocarbons that only has single bonds only. No further atoms can be added to the molecule without removing one of the atoms already there.

Question 22

What is an unsaturated hydrocarbon

Answer 22

Contains carbon to carbon multiple bonds (double or triple bonds), the spare electrons in the multiple bond can be used to add more atoms to the molecule.

Question 23

What is the general formula

Answer 23

The simplest algebraic formula of a member of a homologous series

Question 24

What is a functional group

Answer 24

A group of atoms responsible for the characteristic reactions of a compound

Question 25

What is a homologous series

Answer 25

Is a series of organic compounds having the same functional group with each successive member differing by CH2

Question 26

What do all the members of a homologous series have

Answer 26

Similar chemical properties The same general molecular formula

Question 27

What changes in a homologous series

Answer 27

The physical properties gradually change as the number of carbon atoms increases.

Question 28

When are commas and dashes used

Answer 28

Commas between numbers and dashes between numbers and letters

Question 29

What are structural isomers

Answer 29

They have the same molecular formula but a different structural formula.

Question 30

What are positional isomers

Answer 30

For compounds that contain a functional group, this can be positioned at different positions along the carbon chain.

Question 31

What can molecules sometimes have (functional groups and molecular formula)

Answer 31

Sometimes 2 molecules contain different functional groups, but have 2 different structural formulas but the same molecular formula.

Question 32

What does a basic chemical reaction show us and what does it not show us

Answer 32

The reactants, the products and the stoichometry, however it doesn’t tell us how a reaction takes place.

Question 33

What are curly double headed arrows used to show

Answer 33

The movement of a pair of electrons when bonds are broken or made.

Question 34

What can covalent bonds be broken by

Answer 34

The shared pairs of electrons between a toms can be broken by either homolytic or heterolytic fission.

Question 35

What is homolytic fission

Answer 35

where each of the bonded atoms takes one of the shared pair of electrons from the bond Each atom now has a single unpaired electron

Question 36

What is a radical

Answer 36

An atom or group of atoms with a single unpaired electron = radical

Question 37

What is used to symbolise a radical

Answer 37

A dot is placed next to the atom or molecule

Question 38

Draw the homolytic fission of a c-c bond in ethane

Question 39

What occurs in heterolytic fission

Answer 39

The covalent bond breaks One of the atom takes both of the electrons from the bond The atom that takes both electrons becomes a negatively charged ion The atom that doesn’t take the electrons becomes a positively charged ion

Question 40

What is shown in a mechanism and how is it represented

Answer 40

The movement of electrons This is shown using curly arrows A half arrow represents the movement of a single unpaired electron A full arrow represents the pair

Question 41

Draw the mechanism for the homolytic fission of bromine

Answer 41

DRAW IT

Question 42

Draw the heterolytic fission of H3C - CL

Question 43

What is an addition reaction and an example and what breaks

Answer 43

Two reactants join together to form one product E.g unsaturated alkene + water -> alcohol The double bond breaks to form a saturated compound

Question 44

What occurs in a substitution reaction

Answer 44

Atoms, or groups of atoms are replaced by a different atom or group

Question 45

What occurs in elimination

Answer 45

Involves the removal of a small molecule from a larger one. One reactant forms two products.