3.3.1- introduction to organic chemistry

Question 1

define empirical formula

Answer 1

simplest whole number ratio of atoms in a molecule

Question 2

define molecular formula

Answer 2

gives the actual number of atoms of different elements in a molecule

Question 3

define displayed formula

Answer 3

shows every atom and every bond in a molecule

Question 4

define structural formula

Answer 4

shows arrangement of atoms in a molecule without showing every bond

Question 5

define skeletal formula

Answer 5

drawn as lines with each vertex being a carbon atom. Carbon atoms aren’t drawn, assumed each C atom has all unspecified bonds as C-H

Question 6

define homologous series

Answer 6

a group of compounds with the same functional group/general formula. Compounds in a homologous series will react similarly.

Question 7

Alkanes

Answer 7

-hydrocarbon
- have no c=c double bonds so are saturated
- end in ‘ane’
-general formula - CnH2n+2

Question 8

Alkenes

Answer 8

-hydrocarbon
-has C=C double bonds so is unsaturated
-ends in ‘ene’
-has C=C functional group
- number needed for naming (where double bond is)

Question 9

Halogenoalkanes

Answer 9

• has additional group 7 element
• C-X functional group where X is a group 7 element
  -Cl= chloro, Br= bromo, I= iodo
• need number for naming

Question 10

Alcohols

Answer 10

• ends in ‘ol’ (sometimes number needed)
  OH functional group
• general formula= CnH2n+1OH

Question 11

Carboxylic Acids

Answer 11

• ends in ‘anoic acid’
• COOH functional group
• always at end of chain (no number needed for naming)

Question 12

Aldehydes

Answer 12

• have C=O functional group
• ends in ‘anal’
• at end of chain

Question 13

Ketones

Answer 13

• have C=O functional group
• ends in ‘one
• middle of chain
• sometimes need numbers for naming

Question 14

prefix for CH3 group

Answer 14

methyl

Question 15

prefix for C2H5 group

Answer 15

ethyl

Question 16

prefix for C3H7 group

Answer 16

propyl

Question 17

prefix for C4H9 group

Answer 17

butyl

Question 18

define structural isomers

Answer 18

when molecules have the same molecular formula but a different structural formula

Question 19

define positional isomerism

Answer 19

functional group is attached to the main chain at a different place

Question 20

define functional group isomerism

Answer 20

same atoms but a different functional group due to a different arrangement of atoms

Question 21

define chain isomerism

Answer 21

hydrocarbon chain organised differently, e.g. branched chains

Question 22

define stereoisomerism

Answer 22

when molecules have the same structural and molecular formula, but have a different arrangement of atoms in space

Question 23

What is E-Z isomerism?

Answer 23

• E-Z isomerism is caused by limited rotation about C=C double bonds
• highest values (atomic number) opposite = E
• highest values (atomic number) together= Z

Question 24

priority rules

Answer 24

• choose lowest number as top priority
• if numbers are the same then use priority list (halogens-alkyl-alkenes-everything else)