11. Intro to organic chemistry

Question 1

Define hydrocarbon

Answer 1

• Compounding consisting of hydrogen and carbon only

Question 2

Define saturated

Answer 2

• Contains single carbon-carbon bonds only

Question 3

Define unsaturated

Answer 3

• Contains a C=C double bond

Question 4

Define molecular formula

Answer 4

• Formula which shows the actual number of each type of atom

Question 5

Define empirical formula

Answer 5

• Shows the simplest whole number ratio of atoms of each element in the compound

Question 6

Define general formula

Answer 6

• Algebraic formula for a homologous series
  e.g. CnH2n

Question 7

Define structural formula

Answer 7

• Shows the final details that shows the arrangement of atoms in a molecule
  e.g. butane: CH3CH2CH2CH3 or CH3(CH2)2CH3,

Question 8

Define displayed formula

Answer 8

• Show all the covalent bonds and atoms present in a molecule

Question 9

Describe how you would draw displayed formulae

Answer 9

*

Question 10

Define skeletal formula

Answer 10

• Shows the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups

Question 11

Define functional group

Answer 11

• An atom or group of atoms which when present in different molecules causes them to have similar chemical properties

Question 12

Define homologous series

Answer 12

• Families of organic compounds with the same functional group and same general formula

Question 13

Describe the characteristics of a homologous series

Answer 13

• A gradual change in physical properties
• Each member differs by CH2 from the last
• Same chemical properties

Question 14

Name different examples of homologous series

Answer 14

• Alkane
• Alkenes
• Alcohols
• Halogenoalkanes
• Aldehydes
• Ketones
• Carboxylic acids
• Esters

Question 15

Name the functional group and prefix/suffix of alkane?

Answer 15

• C-C
• -ane

Question 16

Name the functional group and prefix/suffix of alkenes

Answer 16

• C=C
• -ene

Question 17

Name the functional group and prefix/suffix of alcohols

Answer 17

• C-CH

Question 18

Halogenoalkanes

Question 19

aldehydes

Question 20

ketones

Question 21

carboxylic acids

Question 22

esters

Answer 23

• When compounds contain more than one functional group, the order of precedence determines which groups are named with prefix or suffix forms.
• The highest precedence group takes the suffix (and the lowest number on the carbon chain), with all others taking the prefix form.
• However, double and triple C-C bonds only take suffix form.
• Order of priority highest first:
  Carboxylic acids >aldehydes>ketones>alcohols>alkenes>halogenoalkanes

Question 24

State the general rules for naming carbon chains

Answer 24

• Count longest carbon chain and name appropriately using no. of carbons
• Find any branched chains and count how many carbons they contain from the shortest end
• Add the appropriate prefix for each branch chain
  e.g. -CH3: methyl, -C2H5 - ethyl - C3H7 propyl

Question 25

carbon double bond

Answer 25

* must be displayed too e.g. but 1 ene

Question 26

code

Answer 26

meth eth prop but pent hex hept oct non dec

Question 27

Basic rules for naming functional groups

Answer 27

The functional group is named by a prefix or suffix. e.g. bromoethane, ethanol, propene

Answer 28

When using a suffix, add in the following way : If the suffix starts with a vowel- remove the –e from the stem alkane name e.g. Propan-1-ol, butan-1-amine, ethanoic acid, ethanoylchloride, butanamide If the suffix starts with a consonant or there are two or more of a functional group meaning di, or tri needs to be used then do not remove the the –e from the stem alkane name e.g. Propanenitrile, ethane-1,2-diol, propanedioic acid, propane-1,2,3-triol, pentane-2,4-dione.

Answer 29

The position of the functional group on the carbon chain is given by a number – counting from the end of the molecule that gives the functional group the lowest number. For aldehydes, carboxylic acids & nitriles, the functional group is always on carbon 1.

Answer 30

We only include numbers, however, if they are needed to avoid ambiguity.

Question 31

*The functional groups take precedence over branched chains in giving the lowest number

Answer 31

Where there are two or more of the same groups, di-, tri- , tetra-, penta- or hexa- are used. Note the point made above about the addition of ‘e’ to the stem

Answer 32

Words are separated by numbers with dashes  numbers are separated by commas If there is more than one functional group or side chain, the groups are listed in alphabetical order (ignoring any di, tri).

Question 33

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