11.3 Representing the formulae of organic compounds

Question 1

Definition of molecular formula

Answer 1

the number and type of atoms of each element present in a molecule

Question 2

Definition of empirical formula

Answer 2

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

Question 3

Definition of general formula

Answer 3

the simplest algebraic formula for any member of a homologous series

Question 4

General formula of alkanes

Answer 4

CnH2n+2

Question 5

General formula of alkenes

Answer 5

CnH2n

Question 6

General formula of alcohols

Answer 6

CnH2n+1OH

Question 7

General formula of carboxylic acids

Answer 7

CnH2nO2

Question 8

General formula of ketones

Answer 8

CnH2nO

Question 9

What does displayed formula show?

Answer 9

shows the relative positioning of all the atoms in a molecule and the bonds between them

Question 10

What is the structural formula

Answer 10

the smallest amount of detail necessary to show the arrangement of the atoms in a molecule

eg. butane = CH3CH2CH2CH3

Question 11

What are the rues for skeletal formula

Answer 11

-a line represents a single bond
-an intersection of two lines represents a carbon atom
-the end of a line represents a -CH3 group

Question 12

What is skeletal formula

Answer 12

-simplified organic formula where you remove (for hydrocarbon chain):
-all of the carbon and c hydrogen labels from carbon chains
-any bonds to hydrogen atoms