Organic molecules

Question 1

Define an alkane

Answer 1

A homologous series of saturated hydrocarbons

Question 2

What is an alkane structural isomer

Answer 2

Same molecular formula, different structural formula

Question 3

How do you name structural isomers of alkanes

Answer 3

Find the longest carbon chain
Name the side chain
Show which carbon the side chain is attached to

Question 4

Define an alkene

Answer 4

An unsaturated molecule (contains a double bond)

Question 5

Define a haloalkane

Answer 5

An alkane where one or more of the hydrogens have been replaced by a halide

Question 6

Define an alcohol

Answer 6

Contain an OH group

Question 7

Define a carboxylic acid

Answer 7

Contains an COOH group

Question 8

Define a ketone

Answer 8

Contains a =O bond in the middle of the molecule

Question 9

Define an aldehyde

Answer 9

Contains a =O and -H group on the end of the molecule

Question 10

What is E-Z isomerism and how do you identify it

Answer 10

E-Z isomerism occurs in alkenes because they have a non-rotational double bond. Therefore if the priority groups are on the same side of the molecule, we call it Z isomerism and if they are on different sides it is called E isomerism

Question 11

What is the branching effect

Answer 11

If the molecule contains a lot of branches, the boiling point is lower

Question 12

What is the trend in boiling point and chain length in hydrocarbons

Answer 12

Longer chains = higher boiling points

Question 13

What is the general formula for the combustion of alkanes

Answer 13

CnH2n+2 + O2 -> nCO2 + n+1H2O

Question 14

Advantages of burning hydrocarbons for fuel

Answer 14

Plentiful source of energy
Cheaper than many renewable sources
Universal fuel
Efficient sources of fuel

Question 15

Disadvantages of burning hydrocarbons for fuel

Answer 15

Carbon dioxide emissions contribute to global warming
Expensive power plants
Pollution caused by oil spills

Question 16

Describe the structure of the double bond

Answer 16

A sigma bond between the S orbital electrons and a pi bond between the P orbital electrons which creates an area of negativity around the bond because the pi bond sticks out

Question 17

Name properties and uses of haloalkanes

Answer 17

Low boiling point
Insoluble in water

Used as refrigerants, solvents and anaesthetics

Question 18

Describe CFCs and problems associated with them

Answer 18

Chloro-fluorocarbons were used as propellants in aerosols for years before it was discovered they are responsible for eroding the ozone layer

Question 19

Define a biofuel

Answer 19

A fuel grown from natural resources

Question 20

Advantages of biofuels

Answer 20

Renewable
Carbon neutral
More economic security for countries that don’t have fossil fuels

Question 21

Disadvantages of biofuels

Answer 21

Use of free land
Use of resources
Not completely carbon neutral because we have to build power plants and transport them etc..

Question 22

How are alcohols classified

Answer 22

Primary - OH group joined to the end of the molecule
Secondary - OH group joined to carbon that is joined to two other carbons
Tertiary - OH group joined to carbon that is attached to three other carbons