Organic Chemistry - The Basics (pages 88-91)

Question 1

There are Loads of ways of representing Organis Compounds.

What is the type of fomula and what do it show you for:

General Formula?

Answer 1

It shows you an algebraic formula that can describe any member of a family of compounds

formula for Butan-1-ol:

CnH2n+1OH (for all alchols)

(Butan-1-ol is maianly used in the production of varnishes)

Question 2

Explain what Empirical formula shows you, and its formula for Butan-1-ol?

Answer 2

The simples whole number ratio of atoms of each element in a compound (cancel the numbers down if possible). (so ethane, C2H6 has the empirical formula CH³)

formula for butan-1-ol is C4H10O

see table on page 88.

Question 3

Explain what the Molecular Formula is, and what is the Formular for Butan-1-ol

Answer 3

It shows you the actual number of atoms of each element in a molecule.

Butan-1-ol is C4H10O

Question 4

Explain the type of formula ‘Structural Formula shows you’ and what is the Formula for Butan-1-ol

Answer 4

Structural formula show the arrangement of atoms carbon by carbon, with the attached hydrogens and functional groups.

Formula for Butan-1-ol is:

CH3CH2CH2CHOH (this could also be written as: CH3(CH2)3OH

Question 5

Explain the type of formula for Skeletal Formula, and what is the formula for Butan-1-ol?

Answer 5

Skeletal formular shows the bonds of the carbon skeleton only, with any functional groups. The hydrogen and carbon atoms aren’t shown. This is handy for drawing large complicated structures, like cyclic Hydrocarbons.

skeletal formula for Butan-1-ol is: /\/\OH (not the best sample, so please see table for formula on page 88).

Question 6

Explain the type of formula for ‘Displayed Formula - explain what it shows you, and what is the formula for Butan-1-ol

Answer 6

Displayed formula shows how the atoms are arranged, and all the bonds between the

the formula for butan-1-ol (displayed formula) see formula on page 88.

Question 7

What is Organic Chemistry more about?

Groups or individual compounds?

Answer 7

organic chemistry is more about GROUPS of similar chemicals than individual compounds.

Question 8

What are organic chemistry groups of similar chemicals called?

Answer 8

Homologous Series.

(a functional group is a group of atoms in a molecule resonsible for the characteristic reactions of that compound).

Question 9

What is Homologous Series?

Answer 9

is a bunch of organic compounds that have the same functional group and general formula.

Consecutive members of a homologous series differ by -CH2-

Question 10

What is the simplest homologous series?

Answer 10

Alkanes.

They’re straigh chain molecules that contain only carbon and hydrogen atome. There’s a lot more about the alkanes on pages 92-95.

Question 11

What is the general formula for alkanes?

Answer 11

CaH2n + 2.

so the first alkane in the series is C1H(2x1)+2 = CH4 (youdon’t need to write the 1 in C1), the second is C2H(2x2)+2 = C2H6, the seventeenth is C17H(2x17)+2 = C17H36, and so on…

Question 12

What is the Homologus series (you need to know them).

Answer 12

Homologous Series:

alkanes
branched alkanes
alkenes
haloalkanes
alcohols
aldehydes
ketones
cycloalkanes
carboxylic acids
esters

Question 13

What is the homologous series prefix or suffix for Alkanes, and give an example for propane?

Answer 13

prefix or suffix:

-ane

example of propane - CH3CH2CH3

Question 14

What is the homologous series prefix or suffix for branched alkanes, and give example for methylpropane?

Answer 14

prefix or suffix = alkyl- (-yl)

example of methylpropane - CH3CH(CH3)CH3

Question 15

What is the homologous series prefix or suffex for alkenes, and give example of propene?

Answer 15

prefix or suffix - ene

example of propene - CH3CH=CH2

Question 16

What is the homologous series prefix or suffix for haloalkanes, and give example of chloroethane?

Answer 16

prefix or suffix - chloro-/bromo-/iodo-

example of chloroethane = CH3CH2C1

Question 17

What is the homologous series prefix or suffix for alchols, and give example using ethanol?

Answer 17

prefix or suffix = -ol

example of ethanol = CH3CH2OH

Question 18

What is the homologous series prefix or suffix for aldehydes, and give example for ethanal?

Answer 18

prefix or suffix = -al

example of ethanal = CH3CHO

Question 19

What is the homologous series prefix or suffix for ketones, and give example with propanone?

Answer 19

prefix or suffix = -one

example with propanone = CH3COCH3

Question 20

What is the homologous series prefix or suffix for cyloalkanes, and give example with cyclohexane?

Answer 20

prefix or suffix = cyclo- … -ane

example cyclohexane = C6H12

Question 21

What is the homologous series prefix or suffix for carboxylic acids, give example with ethanoic acid?

Answer 21

prefix or suffix = -oic acid

example for ethanoic acid = CH3COOH

Question 22

What is the homologous series prefix or suffix for Esters, give example with methyl propanoate?

Answer 22

Prefix or suffix = alkyl- … -anoate

example for methyl propanoate = CH3CH2COOCH3

Question 23

There are different types of Carbon Skeleton.

All organic compounds contain a carbon skeleton. this can be either ?

Answer 23

Aromatic or aliphatic.

Aromatic compounds contain a benzene ring - you can draw benzene rings in two ways.

see diagram 1 on page 89 of what the skeltal formulas look like. (each point represents a carbon atom)

Question 24

What do Aliphatic compounds contain?

Answer 24

carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings.

Question 25

If an Aliphatic compound contains a (non-aromatic) ring, it can then be called what?

Answer 25

alicyclic

Question 26

Organic compounds may be saturated or unsaturated.

What do Saturated compounds contain?

Answer 26

saturated compounds only contain carbon-carbon single bonds - like alkanes.

Question 27

Organic compounds my be saturated or unsaturated.

What do Unsaturated compounds have?

Answer 27

unsaturated compounds can have carbon- carbon double bonds, triple bonds or aromatic groups.

Question 28

What is an alkyl group?

Answer 28

is a fragment of a molecule, with general formula CnH2n+1

see diagram on page 89 of alkyl group.

Question 29

Nomenclature is a fancy word for naming what?

Answer 29

organic compounds.

organic compounds used to be given whatever name people fanied, but these names led to confusion between different countries.

so the IUPAC system for naming organic compounds was invented as an international language for chemistry. It can be used to give any organic compound a systematic name using the rules of nomenclature. (see table on page 89)

(IUPAC = International Union of Pure and Applied Chemistry)

Question 30

Explain how you use the Nomenclature system is?

Answer 30

1) count the carbon atoms in the longest continous chain. - this gives you the stem. (see table on page 89)
2)The main functional group of the molecule usually tells you what homologous series the molecule is in, and so gives you the prefix or suffix (see table on page 88)
3) Number the longest carbon chain so that the main functional group has the lowest possilbe unumber. If there’s mre than one longest chain, pick the one with the most side-chains.
4) Any side-chains or less important functional groups are added as prefixes at the start of the name. Put them in alphabetical order, after the number of the carbon atom each is attached to.
5) If there’s more than one identical side-chain of functional group, use di-(2), tri-(3), or tetra-(4) before that part of the name - but ignore this when working out the alphabetical order.

look at the example on page 89 of this explination.

Question 31

Isomers have the same Molecular formular. what do this mean?

Answer 31

two molecules are isomer of one another if they have the same molecular formular but the atoms are arranged differently.

Question 32

What are the two types of Isomers you need to know about?

Answer 32

Structural Isomers and Stereoisomer

Question 33

What are Structural Isomers?

Answer 33

Structural Isomers have different structural arrangements of atoms.

In structural isomers , the atoms are connected in different ways, so although the molecular formula is the same, the structural formula is different.

Question 34

What are the three different types of structural isomer?

Answer 34

1) chain Isomers
2) Positional Isomers
3)Functional Group Isomers

Question 35

What are Structural Chain Isomers?

Answer 35

The carbon skeleton can be arranged differently - for example, as a straight chain, or branched in different ways

These isomers have similar chemical properties, but thier physical properties, like boiling point, will be different because of the change in shape of the molecule.

look at diagram 1 of Butane and Methylpropane structural Chain Isomers.

Question 36

What are structural Positional Isomers?

Answer 36

The skeleton and the functional group could be the same, only with the functional group attached to a different carbon atom.

These also have different physical properties, and the chemical properties might be different too.

see diagram 2 of structure on page 90 of Butan-1-ol and Butan-2-ol

Question 37

What is the structural functional group isomers?

Answer 37

The same atoms can be arranged into different functional groups. These have a very different physical and chemical properties.

see diagram 3 on page 90 of the structure for butanoic acid and methyl propannoate.

Question 38

What can fool or confuse you, what can look like an Isomer might not be?

Answer 38

Atoms can rotate as much as they like around single C-C bonds.

Remember this when you work out structural isomers - sometimes what looks like an isomer isnt.
for example, there are no chain isomer and only two positional isomer of C3H7Br on diagram 1 and 2 on page 91) make sure you know the difference.

Question 39

Explain the difference between molecular formulas and structural formulas?

Answer 39

a structural formulas is different from a molecular formular in that it shows the arrangement of the molecule where the molecular formular only shows the number of atoms of each element.

Question 40

What is meant by the term ‘homologous series’?

Answer 40

is a series of organic compounds containing the same functional group with successive members differing by CH2.

Question 41

In what order should prefixes be listed in the name of an organic compound?

Answer 41

Teh IUPAC system is used for naming organic compounds.

Nomenclature - fancy word for naming organic compounds.

in summary, the name of the compound is written out with the substituents in alphabetical order followed by the base name (derived from the number of carbons in the parent chain). Commas are used between numbers and dashes are used between letters and numbers. There are no spaces in the name.

Question 42

What are isomers?

Answer 42

Two molecules are isomers of one another if they have the same molecular formla but the atoms are arranged fifferently.

you need to know about wwo types of isomers, Structural isomers and steroisomers.

Question 43

Name the three types of structural isomerism?

Answer 43

Chain Isomers
Positional Isomers
Functional Group Isomers

Question 44

1 - bromo-2-methylpentane is prepaired from 2-methylpantan-1-ol in this reaction:

C6H13OH + NaBr + H2SO4&raquo_space;» C6H13BR + NzHSO4 + H2O

a) draw the displayed formulas for 1-bromo-2methylpentane and 2-menthylpentan-1-ol (2marks)
b) what is the functional group in 2-methylpentan-1-ol and why is it necessary (2marks)

Answer 44

a) look at diagram 1 and 2 on page 241, question 91 for diagram answer. [1 mark for each diagram]
b) -OH (hydroxyal) [1 mark]
it could be attracted to any of the five carbons OR because the positon of the -OH group affects its chemistry [1mark]

Question 45

Give the systematicnames of the following compounds:

A) see diagram Q2a on page 91, B) see diagram, C) see diagram (3 marks)

Answer 45

a) 4-chloro-pentanoci acid [1mark]
b) methylbutane [1mark] theres only acutally one type of methylbutane..You can’t have 1-methylbutane - it’d be exactly the same a pentane.
c) Dimethylpropane [1mark] there’s only one type of dimethylpropane - 1,1-dimethylopropane and 1,2-dimethylopropane are actually methylbutane

Question 46

a) how many chain isomers are ther of the alkane C6H14? (1 mark)

A 4, B 5, C 6, D 7

b) explain what is meant by the term ‘chain isomerism’? (2 marks)

Answer 46

a) B[1mark]
b) the same molecular formlar [1mark] but different arrangemtns of the carbon skeleton [1mark]